Name: using a cell-tracer injection to investigate the origin of neointima-forming cells in a rat saccular side wall model
Uploaded: 2022-03-16T14:45:00
Description: Watch this Scientific Journal Video about Using a Cell-Tracer Injection to Investigate the Origin of Neointima-Forming Cells in a Rat Saccular Side Wall Model at JoVE.com

The authors thank Alessandra Bergadano, DVM, PhD, for the dedicated supervision of long-term animal health. This work was supported by the research funds of the Research Council, Kantonsspital Aarau, Aarau, Switzerland, and the Swiss national science foundation SNF (310030_182450).

Veterinary support was performed according to institutional guidelines. Experiments were approved by the Local Ethics Committee, Switzerland (BE 60/19). The ARRIVE guidelines and 3R principles have been strictly followed6,7. Thirty-one male Lewis rats, 12 weeks old and weighing 492&#160;&#177; 8 g, were included. House all rats at a room temperature of 23 &#176;C and a 12 h light/dark cycle. Provide free access to water and pellets. Statistical analyses have been...

<ol>
	<li>Vergouwen, M. D., 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=Definition+of+delayed+cerebral+ischemia+after+aneurysmal+subarachnoid+hemorrhage+as+an+outcome+event+in+clinical+trials+and+observational+studies:+proposal+of+a+multidisciplinary+research+group.">Definition of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage as an outcome event in clinical trials and observational studies: proposal of a multidisciplinary research group.</a> Stroke. 41 (10), 2391-2395 (2010).</li><li>Macdonald, R. L., 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=Preventing+vasospasm+improves+outcome+after+aneurysmal+subarachnoid+hemorrhage:+rationale+and+design+of+CONSCIOUS-2+and+CONSCIOUS-3+trials.">Preventing vasospasm improves outcome after aneurysmal subarachnoid hemorrhage: rationale and design of CONSCIOUS-2 and CONSCIOUS-3 trials.</a> Neurocritical Care. 13 (3), 416-424 (2010).</li><li>Wanderer, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Levosimendan+as+a+therapeutic+strategy+to+prevent+neuroinflammation+after+aneurysmal+subarachnoid+hemorrhage.">Levosimendan as a therapeutic strategy to prevent neuroinflammation after aneurysmal subarachnoid hemorrhage.</a> Journal of Neurointerventional Surgery. , (2021).</li><li>Wanderer, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aspirin+treatment+prevents+inflammation+in+experimental+bifurcation+aneurysms+in+New+Zealand+White+rabbits.">Aspirin treatment prevents inflammation in experimental bifurcation aneurysms in New Zealand White rabbits.</a> Journal of Neurointerventional Surgery. 14 (2), 189-195 (2021).</li><li>Gruter, B. E., 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=Patterns+of+neointima+formation+after+coil+or+stent+treatment+in+a+rat+saccular+sidewall+aneurysm+model.">Patterns of neointima formation after coil or stent treatment in a rat saccular sidewall aneurysm model.</a> Stroke. 52 (3), 1043-1052 (2021).</li><li>Kilkenny, 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=Animal+research:+reporting+in+vivo+experiments:+the+ARRIVE+guidelines.">Animal research: reporting in vivo experiments: the ARRIVE guidelines.</a> British Journal of Pharmacology. 160 (7), 1577-1579 (2010).</li><li>Tornqvist, E., 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=Strategic+focus+on+3R+principles+reveals+major+reductions+in+the+use+of+animals+in+pharmaceutical+toxicity+testing.">Strategic focus on 3R principles reveals major reductions in the use of animals in pharmaceutical toxicity testing.</a> PLoS One. 9 (7), 101638 (2014).</li><li>Nevzati, E., 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=Aneurysm+wall+cellularity+affects+healing+after+coil+embolization:+assessment+in+a+rat+saccular+aneurysm+model.">Aneurysm wall cellularity affects healing after coil embolization: assessment in a rat saccular aneurysm model.</a> Journal of Neurointerventional Surgery. 12 (6), 621-625 (2020).</li><li>Marbacher, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Helsinki+rat+microsurgical+sidewall+aneurysm+model.">The Helsinki rat microsurgical sidewall aneurysm model.</a> Journal of Visualized Experiments: JoVE. (92), e51071 (2014).</li><li>Nevzati, E., 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=Biodegradable+magnesium+stent+treatment+of+saccular+aneurysms+in+a+rt+model+-+introduction+of+the+surgical+technique.">Biodegradable magnesium stent treatment of saccular aneurysms in a rt model - introduction of the surgical technique.</a> Journal of Visualized Experiments: JoVE. (128), e56359 (2017).</li><li>Gruter, B. E., 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=Testing+bioresorbable+stent+feasibility+in+a+rat+aneurysm+model.">Testing bioresorbable stent feasibility in a rat aneurysm model.</a> Journal of Neurointerventional Surgery. 11 (10), 1050-1054 (2019).</li><li>Kadirvel, 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=Cellular+mechanisms+of+aneurysm+occlusion+after+treatment+with+a+flow+diverter.">Cellular mechanisms of aneurysm occlusion after treatment with a flow diverter.</a> Radiology. 270 (2), 394-399 (2014).</li><li>Li, Z. F., 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=Endothelial+progenitor+cells+contribute+to+neointima+formation+in+rabbit+elastase-induced+aneurysm+after+flow+diverter+treatment.">Endothelial progenitor cells contribute to neointima formation in rabbit elastase-induced aneurysm after flow diverter treatment.</a> CNS Neuroscience &amp; Therapeutics. 19 (5), 352-357 (2013).</li><li>Marbacher, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intraluminal+cell+transplantation+prevents+growth+and+rupture+in+a+model+of+rupture-prone+saccular+aneurysms.">Intraluminal cell transplantation prevents growth and rupture in a model of rupture-prone saccular aneurysms.</a> Stroke. 45 (12), 3684-3690 (2014).</li><li>Frosen, J., 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=Contribution+of+mural+and+bone+marrow-derived+neointimal+cells+to+thrombus+organization+and+wall+remodeling+in+a+microsurgical+murine+saccular+aneurysm+model.">Contribution of mural and bone marrow-derived neointimal cells to thrombus organization and wall remodeling in a microsurgical murine saccular aneurysm model.</a> Neurosurgery. 58 (5), 936-944 (2006).</li><li>Marbacher, S., Niemela, M., Hernesniemi, J., Frosen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recurrence+of+endovascularly+and+microsurgically+treated+intracranial+aneurysms-review+of+the+putative+role+of+aneurysm+wall+biology.">Recurrence of endovascularly and microsurgically treated intracranial aneurysms-review of the putative role of aneurysm wall biology.</a> Neurosurgical Review. 42 (1), 49-58 (2019).</li><li>Frosen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Smooth+muscle+cells+and+the+formation,+degeneration,+and+rupture+of+saccular+intracranial+aneurysm+wall--a+review+of+current+pathophysiological+knowledge.">Smooth muscle cells and the formation, degeneration, and rupture of saccular intracranial aneurysm wall--a review of current pathophysiological knowledge.</a> Translational Stroke Research. 5 (3), 347-356 (2014).</li><li>Fang, X., 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=Bone+marrow-derived+endothelial+progenitor+cells+are+involved+in+aneurysm+repair+in+rabbits.">Bone marrow-derived endothelial progenitor cells are involved in aneurysm repair in rabbits.</a> Journal of Clinical Neuroscience. 19 (9), 1283-1286 (2012).</li><li>Morel, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sex-related+differences+in+wall+remodeling+and+intraluminal+thrombus+resolution+in+a+rat+saccular+aneurysm+model.">Sex-related differences in wall remodeling and intraluminal thrombus resolution in a rat saccular aneurysm model.</a> Journal of Neurosurgery. , 1-14 (2019).</li><li>Gruter, B. E., 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=Fluorescence+video+angiography+for+evaluation+of+dynamic+perfusion+status+in+an+aneurysm+preclinical+experimental+setting.">Fluorescence video angiography for evaluation of dynamic perfusion status in an aneurysm preclinical experimental setting.</a> Operative Neurosurgery. 17 (4), 432-438 (2019).</li><li>Marbacher, S., Strange, F., Frosen, J., Fandino, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preclinical+extracranial+aneurysm+models+for+the+study+and+treatment+of+brain+aneurysms:+A+systematic+review.">Preclinical extracranial aneurysm models for the study and treatment of brain aneurysms: A systematic review.</a> Journal of Cerebral Blood Flow &amp; Metabolism. 40 (5), 922-938 (2020).</li><li>Ravindran, K., 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=Mechanism+of+action+and+biology+of+flow+diverters+in+the+treatment+of+intracranial+aneurysms.">Mechanism of action and biology of flow diverters in the treatment of intracranial aneurysms.</a> Neurosurgery. 86, 13-19 (2020).</li><li>Marbacher, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Loss+of+mural+cells+leads+to+wall+degeneration,+aneurysm+growth,+and+eventual+rupture+in+a+rat+aneurysm+model.">Loss of mural cells leads to wall degeneration, aneurysm growth, and eventual rupture in a rat aneurysm model.</a> Stroke. 45 (1), 248-254 (2014).</li><li>Morosanu, C. O., 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=Neurosurgical+cadaveric+and+in+vivo+large+animal+training+models+for+cranial+and+spinal+approaches+and+techniques+-+systematic+review+of+current+literature.">Neurosurgical cadaveric and in vivo large animal training models for cranial and spinal approaches and techniques - systematic review of current literature.</a> Neurologia i Neurochirurgia Polska. 53 (1), 8-17 (2019).</li><li>Wanderer, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Arterial+pouch+microsurgical+bifurcation+aneurysm+model+in+the+rabbit.">Arterial pouch microsurgical bifurcation aneurysm model in the rabbit.</a> Journal of Visualized Experiments: JoVE. (159), e61157 (2020).</li></ol>

This study demonstrates that neointima formation is mediated via endothelial cells originating in the parent artery of the aneurysm complex but is supported by the recruitment of cells derived from the aneurysm wall in vital aneurysms. Nevertheless, the role of circulating progenitor cells in aneurysm healing remains controversial12,13. Overall, 31 male Lewis rats were included in this investigation; only 4 died prematurely (12.9% mortality).
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Subarachnoid hemorrhage caused by the rupture of an intracranial aneurysm (IA) is a devastating neurosurgical condition associated with high morbidity and mortality1,2,3,4. In addition to microsurgical clipping, which provides direct endothelium-to-endothelium contact, endovascular devices have gained increasing importance over the past decades for treating ruptured and incidentally discovered IAs. The healing response in endovascularly treated IAs mainly depends on neointima formation and thrombus organization. Both are synergic processes, depending on cell migration from the adjacent vessel and the aneurysm wall.5 To date, the origin of endothelial cells in neointima formation of endovascular treated aneurysms remains unclear. There is an ongoing debate in the literature about the source from which neointima-forming cells are recruited.
By using a cell-tracer injection of CM-Dil dye (see the Table of Materials) in the abdominal aorta of rats, we aimed to analyze the role of endothelial cells, originating in the parent artery, in neointima formation at two different FU time points (day 7 and day 21) (Figure 1). An advantage of the model is the direct local cell-tracer incubation in vivo in a parent artery prior to aneurysm suture, allowing FU at later time points. In vivo injection techniques, such as cell-tracer incubation, have not been described in the literature. An advantage of this technique is the direct, one-point, intraoperative, in vivo injection, which makes the model robust and reproducible.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>3-0 resorbable suture</td>
			<td>Ethicon Inc., USA</td>
			<td>VCP428G</td>
			<td></td>
		</tr>
		<tr>
			<td>4-0 non-absorbable suture</td>
			<td>B. Braun, Germany</td>
			<td>G0762563</td>
			<td></td>
		</tr>
		<tr>
			<td>6-0 non-absorbable suture</td>
			<td>B. Braun, Germany</td>
			<td>C0766070</td>
			<td></td>
		</tr>
		<tr>
			<td>9-0 non-absorbable suture</td>
			<td>B. Braun, Germany</td>
			<td>G1111140</td>
			<td></td>
		</tr>
		<tr>
			<td>Atipamezol</td>
			<td>Arovet AG, Switzerland</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bandpass filter blue</td>
			<td>Thorlabs</td>
			<td>FD1B</td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Bandpass filter green</td>
			<td>Thorlabs</td>
			<td>FGV9</td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Bipolar forceps</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Bicycle spotlight</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Board (20 x 10 cm)</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Buprenorphine</td>
			<td>Indivior, Switzerland</td>
			<td>1014197</td>
			<td></td>
		</tr>
		<tr>
			<td>Camera</td>
			<td>Sony NEX-5R, Sony, Tokyo, Japan</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cannula (27-1/2 G)</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Cell count software</td>
			<td>Image-J version 1.52n, U.S. National Institutes of Health, Bethesda, Maryland, USA, https://imagej.nih.gov/ij/</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>CellTracker CM-Dil dye</td>
			<td>ThermoFisher SCIENTIFIC, USA</td>
			<td>C7000</td>
			<td></td>
		</tr>
		<tr>
			<td>Coil-Device</td>
			<td>Styker, Kalamazoo, MI, USA</td>
			<td></td>
			<td>2 cm of Target 360 TM Ultra, 2-mm diameter</td>
		</tr>
		<tr>
			<td>Desinfection</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Eye-lubricant</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Fentanyl</td>
			<td>Sintetica, S.A., Switzerland</td>
			<td>98683</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Flumazenil</td>
			<td>Labatec-Pharma, Switerzland</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Fluoresceine</td>
			<td>Curatis AG</td>
			<td>5030376</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Fluorescence microscope</td>
			<td>Olympus BX51, Hamburg, Germany; Cell Sens Dimension Imaging software v1.8</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Foil mask</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Glucose (5%)</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Heating pad</td>
			<td>Homeothermic Control Unit, Harvard, Edenbridge, England</td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Isotonic sodium chloride solution (0.9%)</td>
			<td>Fresenius KABI</td>
			<td>336769</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td></td>
			<td></td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Longuettes</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Meloxicam</td>
			<td>Boehringer Ingelheim</td>
			<td>P7626406</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Medetomidine</td>
			<td>Virbac, Switzerland</td>
			<td>QN05CM91</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro needle holder</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Midazolam</td>
			<td>Roche, Switzerland</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Monitoring-system</td>
			<td>Starr Life Sciences Corp., 333 Allegheny Ave, Oakmont, PA 15139, United States</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Needle holder</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>O2-Face mask</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Operation microscope</td>
			<td>OPMI, Carl Zeiss AG, Oberkochen, Germany</td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Oxygen</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Rectal temperature probe</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Scalpell</td>
			<td>Swann-Morton</td>
			<td>210</td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Small animal shaver</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Smartphone</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Sodium dodecyl sulfate (0.1%)</td>
			<td>Sigma-Aldrich</td>
			<td>11667289001</td>
			<td></td>
		</tr>
		<tr>
			<td>Soft feed</td>
			<td>Emeraid Omnivore</td>
			<td></td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Soft tissue forceps</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Soft tissue spreader</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Stainless steel sponge bowls</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Stent-Device</td>
			<td>Biotroni, B&#252;lach, Switzerland</td>
			<td></td>
			<td>modified magmaris device, AMS with polymer coating, 6-mm length, 2-mm diameter</td>
		</tr>
		<tr>
			<td>Sterile micro swabs</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Straight and curved microforceps</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Straight and curved microscissors</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Straight and curved forceps</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Surgery drape</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Surgical scissors</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Syringes 1 mL, 2 mL, and 5 mL</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Tape</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Vascular clip applicator</td>
			<td>B. Braun, Germany</td>
			<td>FT495T</td>
			<td></td>
		</tr>
		<tr>
			<td>Yasargil titan standard clip (2x)</td>
			<td>B. Braun Medical AG, Aesculap, Switzerland</td>
			<td>FT242T</td>
			<td>temporary</td>
		</tr>
	</tbody>
</table>

using a cell-tracer injection to investigate the origin of neointima-forming cells in a rat saccular side wall model

Microsurgical clipping creates a subsequent barrier of blood flow into intracranial aneurysms, whereas endovascular treatment relies on neointima and thrombus formation. The source of endothelial cells covering the endoluminal layer of the neointima remains unclear. Therefore, the aim of the present study was to investigate the origin of neointima-forming cells after cell-tracer injection in the already well-established Helsinki rat microsurgical sidewall aneurysm model.
Sidewall aneurysms were created by suturing decellularized or vital arterial pouches end-to-side to the aorta in male Lewis rats. Before arteriotomy with aneurysm suture, a cell-tracer injection containing CM-Dil dye was performed into the clamped aorta to label endothelial cells in the adjacent vessel and track their proliferation during follow-up (FU). Treatment followed by coiling (n = 16) or stenting (n = 15). At FU (7 days or 21 days), all rats underwent fluorescence angiography, followed by aneurysm harvesting and macroscopic and histological evaluation with immunohistological cell counts for specific regions of interest. 
None of the 31 aneurysms had ruptured upon follow-up. Four animals died prematurely. Macroscopically residual perfusion was observed in 75.0% coiled and 7.0% of stented rats. The amount of cell-tracer-positive cells was significantly elevated in decellularized stented compared to coiled aneurysms with respect to thrombus on day 7 (p = 0.01) and neointima on day 21 (p = 0.04). No significant differences were found in thrombus or neointima in vital aneurysms. 
These findings confirm worse healing patterns in coiled compared to stented aneurysms. Neointima formation seems particularly dependent on the parent artery in decellularized aneurysms, whereas it is supported by the recruitment from aneurysm wall cells in vital cell-rich walls. In terms of translation, stent treatment might be more appropriate for highly degenerated aneurysms, whereas coiling alone might be adequate for aneurysms with mostly healthy vessel walls.

A total of 31 animals were included in the laboratory setting: 27 rats were included in the final statistical analysis; 4 rats died prematurely (12.9% mortality rate). Intraoperatively, breath distension was significantly (p = 0.03) reduced in stent- (12.9 &#956;m &#177; 0.7) compared to coil-treated (13.5 &#956;m &#177; 0.6) rats. Fluorescence angiography was performed for every rat at the end of the final FU. Reperfusion was indicated in all 6 coil-treated animals, whereas reperfusion was observed in only 12.5...

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Using a Cell-Tracer Injection to Investigate the Origin of Neointima-Forming Cells in a Rat Saccular Side Wall Model

We performed a one-point, lipophilic cell-tracer injection to track endothelial cells, followed by an arteriotomy and suturing of sidewall aneurysms on the abdominal rat aorta. Neointima formation seemed dependent on the parent artery in decellularized aneurysms and was promoted by the recruitment from aneurysm wall cells in vital cell-rich walls.

Microsurgical clipping creates a subsequent barrier of blood flow into intracranial aneurysms, whereas endovascular treatment relies on neointima and ...

By using a direct intra-aortal cell-tracer application, we can analyze the role of endothelial cells originating from the parent artery in neointima formation at two different time points. A big advantage of this technique is a direct, one-point, interpretive in-vivo injection which makes this model a robust and reproducible technique. Before the surgery, incubate the arterial pouches from donor rats in 0.1%sodium dodecyl sulfate for 10 hours at 37 degrees Celsius to obtain decellularized aneurysms.Collect these pouches from donor animals a few days before the surgery. To begin, analyze the animal's behavior and inspect the mucus membranes and turgor as part of the preoperative clinical examination. Record the weight of each animal.For anesthesia induction, place all rats in a clean box provided with oxygen until loss of consciousness after five to 10 minutes. Check the depth of anesthesia by the absence of the pedal withdrawal reflex. Place the rats in a supine position and shave the thoracoabdominal area with an electric shaver.Using tape, fixate the rat's paws on a board covered by a heating pad connected to an auto-regulating rectal probe. Insert the rectal probe into the rat's anus to maintain the desired temperature of 37 degrees Celsius with the help of a heating pad. Then install a sensor on the right-hind leg connected to a computerized system for checking vital signs intraoperatively.For perianesthetic care, apply a sterile ophthalmic lubricant to the eyes, and cover them with an opaque foil mask to prevent drying and damage from the surgical lamp. Disinfect the surgical field with povidone iodine, and drape the surgical field in a sterile fashion. Put a micro swab with purple padding under the proximal and distal parts of the aorta to better visualize the artery as soon as it is separated from the caval vein.Then protect the abdomen with white gauze. On the day of operation, dissolve two microliters of the cell-tracer by pipetting in one milliliter of PBS. Transfer the mixture to a one-milliliter syringe fitted with a cannula.Turn off the light in the operating room. Using a microscope, perform the one-point injection in the middle ventral part of the aorta with micro forceps, and carefully inject one milliliter of heparinized 0.9%saline solution. Inject the cell-tracer carefully, and immediately turn off the operating microscope as well.Protect the abdomen with wet gauze again. Let the dye incubate for at least 15 minutes. Then turn on the microscope and operating room lights.Use micro forceps and micro scissors to perform the longitudinal arteriotomy so that its length averages the diameter of the harvested aneurysm. Place the aneurysm beside the aorta before performing arteriotomy to ensure the correct length. Suture the aneurysm with eight to 10 single stitches using a non-absorbable 10-0 suture.Before the final stitch, deliver the coil with a packing density of one centimeter. Either coil or stent treatment can be performed in this model. Then carefully remove the temporary clamps, starting distally, under continuous irrigation with heparinized saline.Close the wound in a layered fashion. At the end of the surgery, reverse the anesthesia with a subcutaneous injection. Let each operated animal recover in a clean cage until fully awake and warm as needed with a heating lamp.Pulled baseline aneurysm volumes for day seven and day 21 did not differ significantly for decellularized or vital aneurysms between the coil or stent treatment groups. Pulled FU volumes for decellularized aneurysms showed a non-significant aneurysm growth in coiled compared to the stented aneurysms. Pulled FU volume was significantly greater in the vital coiled than in the stented group.Amounts of cell-tracer positive cells in the neointima of decellularized aneurysms did not significantly differ between the stent or coiled-treated groups at day seven FU but were significantly higher in stented rats at day 21 FU.No significant differences were noted in vital-aneurysm sutured rats at either seven days or 21 days FU.In decellularized aneurysms at seven days FU, significantly more cell-tracer positive cells remained in the thrombus of the stent-treated compared to the coil-treated group. This difference was not observed in vital aneurysms at seven days FU.Remember to always turn off the lights in the operating room prior to injecting the cell-tracer to prevent fading. Also, let incubate the dye for at least 15 minutes.

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