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The authors have nothing to disclose.

Critical steps in this protocol include the management of anesthesia, anticoagulation, surgical manipulation of the artery/grafted vein, and hemodynamic measurements of the grafted vein. Proper management of anesthesia is critical in this multiple survival surgery model that includes two relatively long operations (typically 3-3.5 h for bilateral vein grafting and 1.5-2.5 h for bilateral graft transduction). We have administered anesthesia both via a nosecone and by endotracheal intubation and found that the intubation improved the survival after the graft transduction surgery, possibly because positive pressure ventilation prevents the atelectasis and associated respiratory failure. Rabbits are challenging to intubate, and intubation-related airway trauma can cause post-operative stridor. However, the challenges and complications of the intubation are a small price to pay for the benefit of eliminating most of the perioperative morbidity and mortality associated with the vein grafting surgery.
Anticoagulation is essential in order to prevent the thrombosis of grafted veins, which can occur after either of the survival surgeries. The thrombosis appears to be an early postoperative event, because the vein grafts that are patent on transcutaneous ultrasound examination 5-7 days postoperatively are nearly always patent at harvest. To prevent the thrombosis after the first surgery (i.e., vein grafting), IV heparin is administered before harvesting the first external jugular vein. Based on the plasma half-life of heparin in rabbits (1-2 h), an additional half dose of IV heparin is administered before harvesting the contralateral external jugular vein. In addition, until both arteriovenous anastomoses of an individual vein graft are complete, we flush the lumens of the carotid artery and the vein graft approximately every 8 min with heparinized normal saline. To avoid graft thrombosis, care should be taken not to damage the vein graft-especially the endothelium-during harvesting and grafting. This includes gentle handling of the vein with surgical instruments and leaving a thin layer of adventitial adipose tissue attached to the vein. We also administer a single dose of topical papaverine to the grafted carotid artery, to prevent or reverse vasospasm, which could contribute to thrombosis.
Meticulous attention to surgical technique is required during the vein grafting surgery. To avoid bleeding at the anastomoses, graft thrombosis, and the introduction of uncontrolled hemodynamic variables, the two arteriotomies must be of the proper length. If an arteriotomy is too short, the vein graft ostial wall will be redundant at the site of anastomosis, creating gaps that allow bleeding. If the arteriotomy is too long, stretching the vein to cover the arteriotomy will bring the vein graft walls in close proximity, making it difficult for the surgeon to avoid suturing the opposing vein graft walls together (essentially guaranteeing postoperative thrombosis). Moreover, if the vein graft lumen is narrowed because the vein was stretched to cover an excessively long arteriotomy, a stenosis will be created that increases shear stress, predisposes to thrombosis33, and potentially alters outcome variables such as neointimal growth and vascular remodeling34,35. In addition, it is important to avoid introducing twists into the vein graft, which could result in lumen narrowing or abnormal flow. To help avoid twisting of the graft, we always align the vein segment along the ventral surface of the common carotid artery and ensure there are no twists in the vein. Because of the potential for variable surgical technique to alter vein graft hemodynamics, and because altered hemodynamics can affect outcome variables independently of treatment, we routinely measure blood flow and graft diameter before vector infusion and at the time of harvest. We use these values to calculate shear stress and pulsatility. Vein grafts with hemodynamic measurements outside of predetermined ranges can be excluded objectively from further analysis, decreasing experimental variability and increasing statistical power.
As we developed this method, we made several modifications. Initially, we attempted vein graft gene transfer during the grafting operation. However, under these circumstances, transgene expression was nearly completely lost by 3 days after gene transfer22. Transgene expression was rapidly lost whether the vein segment was transduced in situ and then grafted or whether the vein was grafted first, and then transduced. Only by delaying transduction until after the vein graft had adapted to the arterial circulation (we waited until 28 days after grafting to perform gene transfer, although a shorter delay might be possible), was the rapid loss of transgene expression avoided22. We also converted from nosecone-delivered anesthesia to endotracheal tube-delivered anesthesia for the second (gene transfer) surgery after experiencing intraoperative and postoperative deaths. In addition, after encountering apparent aspiration pneumonia in a postoperative rabbit, we began to place a small plastic table over the rabbit&#39;s abdomen (under the sterile drapes). The table was positioned to prevent the surgeon from inadvertently leaning on the rabbit&#39;s abdomen, potentially stimulating gastroesophageal reflux and aspiration. We had no more aspiration events after the placement of the table. However, because this placement coincided with the shift to endotracheal intubation, we cannot be sure which intervention is responsible for eliminating aspiration events.
This method also has limitations. In the United States, the use of rabbits instead of rodents necessitates compliance with the requirements of the Laboratory Animal Welfare Act of 1966. Accordingly, investigators using rabbits (or other animals covered by this Act) must have well-equipped operating rooms and expert anesthesiologists and provide a high level of postoperative monitoring and care. The second limitation is that 2 surgeries are required in order to ensure persistent transgene expression22. The second surgery increases the cost of experiments and exposes each rabbit to an additional set of potential operative and perioperative complications. However, we are not aware of any other gene transfer approach that achieves durable transgene expression in vein grafts. The third limitation of this method is that it requires expertise in construction of HDAd vectors and preparation of high-titer HDAd stocks. Many laboratories have expertise with first-generation adenoviral, lentiviral, and adeno-associated viral (AAV) vectors, but relatively few groups have experience with HDAd and would typically need to establish a collaboration to obtain this expertise. The clinical applicability of the method may also be limited. For humans, a second surgery would increase both cost and complication risk. In addition, compared to human saphenous veins (used for coronary and peripheral bypass surgeries), rabbit external jugular veins have very thin walls. It is possible that the wall thickening and remodeling that occurs after grafting a rabbit external jugular vein into the arterial circulation would be attenuated if the vein graft already has a thicker wall. Finally, in experiments in this model lasting up to 6 months, none of the grafted veins developed a stenosis22. Therefore, this method does not appear to model all of the biological processes that contribute to vein graft failure.
In conclusion, the method uses a robust animal model of human vascular disease (rabbits) to generate grafted veins in which transgenes are stably expressed for prolonged periods of time (at least 6 months)22. Stable expression of transgenes in vein grafts will reveal their roles in normal vein graft homeostasis and will clarify their potential for vein graft gene therapy. The method could be improved and made more clinically applicable by the development of techniques that allow percutaneous delivery of vectors to the vein graft, thereby avoiding the second surgery. These techniques might be catheter-based36,37, or they could incorporate specially prepared vectors that are injected into a peripheral vein and then targeted to the vein graft wall, for example by magnetic fields38. The method would also allow testing of vectors other than HDAd for vein graft gene therapy, including lentiviral and AAV vectors as well as non-viral vectors.39,40,41,42

Atherosclerosis is a chronic inflammatory disease in which lipid accumulation and inflammation in the blood vessel wall lead to narrowing of the vessel lumen, heart attacks, strokes, and loss of limbs1,2. Percutaneous interventions (e.g., angioplasty and stenting) and medical therapy (e.g., statins and antiplatelet agents) are useful treatments for atherosclerosis; however, they are often ineffective in treating severe obstructive disease both in the coronary and peripheral circulations. Bypass grafting, using autogenous vein segments, remains a common procedure for treating patients with severe, diffuse coronary and peripheral vascular disease3,4. However, vein grafts placed in both the coronary and peripheral circulations have poor long-term patency rates. In the coronary circulation, approximately 10-20% of vein grafts are occluded at 1 year and 50% are occluded by 10 years5,6.In the peripheral circulation, vein graft failure rates are 30-50% at 5 years7.
Gene therapy is an attractive approach for the prevention of vein graft failure because it can deliver a therapeutic gene product precisely at the site of the disease. Accordingly, numerous preclinical studies have tested vein graft gene therapy8,9. However, essentially all of these studies have examined the efficacy at early time points (2-12 weeks)10,11,12,13,14,15,16,17. We are aware of no evidence that gene-therapy interventions can provide durable (years) protection against late vein graft failure that typically results from neointimal hyperplasia and atherosclerosis4. We developed a method that allows durable transgene expression in grafted veins, and thereby allows the testing of gene-therapy interventions at late as well as early time points. To achieve durable transgene expression, the method incorporates HDAd vectors and a delayed transduction strategy. HDAd vectors provide prolonged transgene expression because they lack viral genes, preventing the recognition (and rejection) of transduced cells by the immune system18,19,20,21. Delayed transduction (performed 28 days after the graft placement) prevents the loss of transduced cells during the arterialization process that occurs early after the grafting22.
Other methods that achieve therapeutic transgene expression in the vein graft wall rely on the transduction of the vein graft at the time of the graft placement10,11,12,15,16,17. When measured serially, transgene expression using this approach declines quickly after the transduction22,23. Accordingly, studies using this approach have not examined the efficacy beyond 12 weeks after the vein grafting, with most not assessing efficacy beyond 4 weeks. In contrast, our method achieves vein graft transgene expression that persists stably for at least 24 weeks and-based on similar studies performed in arteries-likely continues far longer22,24. We are aware of no other vein graft gene therapy intervention that achieves stable transgene expression of this duration.
We used a rabbit model to develop our method. Others have used rodents, rabbits, or larger animals to test vein graft gene therapy10,11,12,15,16,17,25,26. Compared to rodent models, rabbits are more expensive and are subject to more stringent regulatory requirements. However, compared to larger animals (e.g., pigs and dogs), rabbits are far less expensive to purchase and house and much easier to handle. Moreover, rabbit vessels resemble human vessels physiologically27, they are sufficiently large that they can be used for testing percutaneous interventions28,29, and they provide sufficient tissue that multiple endpoints (e.g., histology, protein, RNA) can be examined using a single blood vessel specimen22,30. In addition, when the rabbits with vein grafts are fed with a high-fat diet, they develop vein graft atherosclerosis31,32, which is a common cause of coronary artery bypass vein graft failure4,5. These atherosclerotic rabbit vein grafts can serve as a substrate for testing gene-therapy interventions delivered with this method. The provided protocol can help investigators to master the technical skills required to achieve durable transgene expression in rabbit vein grafts.

<table border="0" cellpadding="0" cellspacing="0" style="width:707px;" width="707">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Disposables</td>
			<td style="width:167px;"></td>
			<td style="width:119px;"></td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">3mL syringe with 24G needle</td>
			<td>Becton Dickinson</td>
			<td>309571</td>
			<td style="width:207px;">2x for vein graft surgery; 2x for gene transfer&#160; surgery</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">1 mL syringe with 27G needle</td>
			<td>Becton Dickinson</td>
			<td>309623</td>
			<td style="width:207px;">2x for vein graft surgery, 5x for gene transfer surgery</td>
		</tr>
		<tr height="20">
			<td height="40" rowspan="2" style="height:40px;width:215px;">19G needle</td>
			<td rowspan="2">Becton Dickinson</td>
			<td rowspan="2">305187</td>
			<td rowspan="2" style="width:207px;">Gene transfer surgery</td>
		</tr>
		<tr height="20">
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">20 mL syringe, luer lock</td>
			<td>Nipro Medical Corp</td>
			<td>JD+20L</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Catheters, 24Ga x 3/4&#8221;</td>
			<td>Terumo Medical Products</td>
			<td>SROX2419V</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">21G needle</td>
			<td>Becton Dickinson</td>
			<td>305165</td>
			<td style="width:207px;">Gene transfer surgery and for 20 mL syringe of saline</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Gauze 4&#8221; x 4&#8221;</td>
			<td>Dynarex</td>
			<td style="width:119px;">3242</td>
			<td style="width:207px;">~10-15 per surgery</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">3-0 silk suture</td>
			<td>Covidien Ltd.</td>
			<td>S-244</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">5-0 silk suture</td>
			<td>Covidien Ltd.</td>
			<td>S-182</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">7-0 polypropylene suture</td>
			<td>CP Medical</td>
			<td>8703P</td>
			<td style="width:207px;">Vein graft surgery</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">7-0 polypropylene suture</td>
			<td>CP Medical</td>
			<td>8648P</td>
			<td style="width:207px;">Gene transfer surgery</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">5-0 polyglycolic acid suture</td>
			<td>CP Medical</td>
			<td>421A</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">3-0 polyglycolic acid suture</td>
			<td>CP Medical</td>
			<td>398A</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Alcohol swabs</td>
			<td>Covidien Ltd.</td>
			<td>6818</td>
			<td style="width:207px;">For the placement of I.V. line</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Catheter plug</td>
			<td>Vetoquinol</td>
			<td>411498</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Ketamine HCl, 100 mg/mL</td>
			<td>Vedco Inc.</td>
			<td>5098916106</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Xylazine, 100 mg/mL</td>
			<td>Akorn Inc.</td>
			<td>4821</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Lidocaine, 20 mg/mL</td>
			<td>Pfizer</td>
			<td>409427702</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Marcaine 0.5%</td>
			<td>Pfizer</td>
			<td>409161050</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Beuthanasia D-Special</td>
			<td>Intervet Inc.</td>
			<td>NDC 00061047305</td>
			<td style="width:207px;">Harvest surgery only</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Buprenorphine HCl, 0.3 mg/mL</td>
			<td>Patterson Veterinary</td>
			<td>12496075705</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Saline IV bag, 0.9% sodium chloride</td>
			<td>Baxter</td>
			<td>2B1309</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Heparin&#160; (5000 U/mL)</td>
			<td>APP Pharmaceuticals</td>
			<td>NDC 63323-047-10</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Papaverine (3.5 mg/ml)</td>
			<td>American Reagent Inc.</td>
			<td>NDC 0517-4002-25</td>
			<td style="width:207px;">Diluted from 30mg/mL stock; Use 1 mL maximum</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Fentanyl patch, 25 mcg/h</td>
			<td>Apotex Corp.</td>
			<td>NDC 60505-7006-2</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Isoflurane</td>
			<td>Multiple vendors</td>
			<td style="width:119px;">Catalog number not available</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">&#160;Viral vector</td>
			<td></td>
			<td style="width:119px;"></td>
			<td style="width:207px;">Gene transfer surgery only</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Surgical Instruments</td>
			<td></td>
			<td style="width:119px;"></td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Metzenbaum needle holder 7&#34; straight</td>
			<td>Roboz</td>
			<td style="width:119px;">RS-7900</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Operating scissors 6.5&#34; straight blunt/blunt</td>
			<td>Roboz</td>
			<td style="width:119px;">RS-6828</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Needle holder /w suture scissors</td>
			<td>Miltex</td>
			<td style="width:119px;">8-14-IMC</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Castroviejo scissors</td>
			<td>Roboz</td>
			<td>RS-5658</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Castroviejo needle holder, 5.75&#34; straight with lock</td>
			<td>Roboz</td>
			<td style="width:119px;">RS-6412</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Stevens scissors 4.25&#34; curved blunt/blunt</td>
			<td>Roboz</td>
			<td style="width:119px;">RS-5943</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Alm retractor 4&#34; 4X4 5mm blunt prongs</td>
			<td>Roboz</td>
			<td style="width:119px;">RS-6514</td>
			<td style="width:207px;">2x</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Backhaus towel clamp 3.5&#34;</td>
			<td>Roboz</td>
			<td style="width:119px;"></td>
			<td style="width:207px;">4x</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Micro clip setting forceps 4.75&#34;</td>
			<td>Roboz</td>
			<td style="width:119px;">RS-6496</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Micro vascular clips, 11 mm</td>
			<td>Roboz</td>
			<td style="width:119px;"></td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Surg-I-Loop</td>
			<td>Scanlan International</td>
			<td style="width:119px;">1001-81M</td>
			<td style="width:207px;">5 cm length</td>
		</tr>
		<tr height="80">
			<td height="80" style="height:80px;width:215px;">Bonaccolto forceps, 4&#8221; (10 cm) long longitudinal serrations, cross serrated tip, 1.2mm tip width</td>
			<td>Roboz</td>
			<td style="width:119px;">RS-5210</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Dumont #3 forceps Inox tip size .17 &#215; .10 mm</td>
			<td>Roboz</td>
			<td style="width:119px;">RS-5042</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Graefe forceps, 4&#8221; (10 cm) long serrated straight, 0.8 mm tip</td>
			<td>Roboz</td>
			<td style="width:119px;">RS-5280</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Halstead mosquito forceps,&#160; 5&#34; straight, 1.3 mm tips</td>
			<td>Roboz</td>
			<td style="width:119px;">RS-7110</td>
			<td style="width:207px;">2x</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Halstead mosquito forceps,&#160; 5&#34; curved, 1.3mm tips</td>
			<td>Roboz</td>
			<td style="width:119px;">RS-7111</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:215px;">Jacobson mosquito forceps 5&#34; curved extra delicate, 0.9 mm tips</td>
			<td>Roboz</td>
			<td style="width:119px;">RS-7117</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Kantrowitz forceps, 7.25&#34; 90 degree delicate, 1.7 mm tips</td>
			<td>Roboz</td>
			<td style="width:119px;">RS-7305</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Tissue forceps 5&#34;, 1X2 teeth, 2 mm tip width</td>
			<td>Roboz</td>
			<td style="width:119px;">RS-8162</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Allis-Baby forceps, 12 cm, 4x5 teeth, 3 mm tip width</td>
			<td>Fine Science Tools</td>
			<td style="width:119px;">11092-12</td>
			<td style="width:207px;">2x</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Adson forceps, 12 cm, serrated, straight</td>
			<td>Fine Science Tools</td>
			<td style="width:119px;">11006-12</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Veterinary electrosurgery handpiece and electrode</td>
			<td>MACAN Manufacturing</td>
			<td style="width:119px;">HPAC-1; R-F11</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Surgical Suite Equipment</td>
			<td></td>
			<td style="width:119px;"></td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Circulating warm water blanket and pump</td>
			<td>Multiple vendors</td>
			<td style="width:119px;">Catalog number not available</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Bair hugger warming unit</td>
			<td>3M</td>
			<td style="width:119px;">Model 505</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">IV infusion pump</td>
			<td>Heska</td>
			<td style="width:119px;">Vet IV 2.2</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Isoflurane vaporizer and scavenger</td>
			<td>Multiple vendors</td>
			<td style="width:119px;">Catalog number not available</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Veterinary multi-parameter monitor</td>
			<td>Surgivet</td>
			<td style="width:119px;">Surgivet Advisor</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:215px;">Veterinary electrosurgery unit</td>
			<td>MACAN Manufacturing</td>
			<td style="width:119px;">MV-9</td>
			<td style="width:207px;"></td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:215px;">Surgical microscope</td>
			<td style="width:167px;">D.F. Vasconcellos</td>
			<td style="width:119px;">M900</td>
			<td style="width:207px;">25X magnification for vein graft surgery; 16X magnification for gene transfer surgery</td>
		</tr>
	</tbody>
</table>

a rabbit model of durable transgene expression in jugular vein to common carotid artery interposition grafts

Vein graft bypass surgery is a common treatment for occlusive arterial disease; however, long-term success is limited by graft failure due to thrombosis, intimal hyperplasia, and atherosclerosis. The goal of this article is to demonstrate a method for placing bilateral venous interposition grafts in a rabbit, then transducing the grafts with a gene transfer vector that achieves durable transgene expression. The method allows the investigation of the biological roles of genes and their protein products in normal vein graft homeostasis. It also allows the testing of transgenes for the activities that could prevent vein graft failure, e.g., whether the expression of a transgene prevents the neointimal growth, reduces the vascular inflammation, or reduces atherosclerosis in rabbits fed with a high-fat diet. During an initial survival surgery, the segments of right and left external jugular vein are excised and placed bilaterally as reversed end-to-side common carotid artery interposition grafts. During a second survival surgery, performed 28 days later, each of the grafts is isolated from the circulation with vascular clips and the lumens are filled (via an arteriotomy) with a solution containing a helper-dependent adenoviral (HDAd) vector. After a 20-min incubation, the vector solution is aspirated, the arteriotomy is repaired, and flow is restored. The veins are harvested at time points dictated by individual experimental protocols. The 28-day delay between the graft placement and the transduction is necessary to ensure the adaptation of the vein graft to the arterial circulation. This adaptation avoids rapid loss of transgene expression that occurs in vein grafts transduced before or immediately after grafting. The method is unique in its ability to achieve durable, stable transgene expression in grafted veins. Compared to other large animal vein graft models, rabbits have advantages of low cost and easy handling. Compared to rodent vein graft models, rabbits have larger and easier-to-manipulate blood vessels that provide abundant tissue for analysis.

The technical proficiency of a new operator must be validated before the operator can use this method to generate experimental data. The first milestone that a new operator must achieve is consistent vein graft patency after both the initial vein-grafting surgery and the subsequent delayed-transduction surgery. Over 90% patency after each of the surgeries is desirable and achievable. The patency can be assessed non-invasively using transcutaneous ultrasound, which we typically perform on postoperative day 5-7. In the rabbits with patent veins, the ultrasound exam will reveal a large blood vessel with brisk caudal-to-cranial blood flow on both sides of the anterior neck (Figure 3A). If either of the vein grafts is occluded, there will be no detectable caudal-to-cranial blood flow on the side(s) with the occluded graft. However, cranial-to-caudal blood flow will still be detected in the internal jugular vein (Figure 3B).
The second milestone that a new operator must achieve is efficient transduction of vein-graft endothelial cells. Here, an adenoviral vector that expresses &#946;-galactosidase is used to evaluate the efficiency of endothelial gene transfer. A new operator in our lab transduced vein grafts with an adenovirus expressing &#946;-galactosidase (AdnLacZ) using the methods described. The grafts were harvested 3 days after the transduction and cut into segments. Some segments were stained with 5-bromo-4-chloro-3-indolyl-&#946;-D-galactopyranoside (X-gal). En face imaging of the luminal surfaces showed vein grafts with efficient transduction (Figure 4A) and poor transduction (Figure 4B). To further evaluate the proficiency of a new operator, &#946;-galactosidase mRNA in the extracts of the transduced vein graft is also measured using quantitative reverse transcriptase-mediated PCR and normalizing the signal to the level of glyceraldehyde phosphate dehydrogenase (GAPDH) mRNA measured in the same vein grafts.
The levels of &#946;-galactosidase mRNA in vein grafts transduced by the new operator were not significantly different from the levels of &#946;-galactosidase mRNA in vein grafts transduced by an experienced operator (Figure 5). If mRNA samples from the vein grafts transduced by an experienced operator are not available for comparison, negative control vein graft mRNA can be generated by transducing vein grafts with a non-expressing control vector (AdNull). We have found that the mean levels of &#946;-galactosidase mRNA in vein grafts transduced by an experienced operator are approximately 1,000-fold higher than the background PCR signal for &#946;-galactosidase mRNA measured in AdNull-transduced grafts (Figure 5).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57231/57231fig1.jpg" /> 
Figure 1. The placement of a reversed right external jugular vein-to-right common carotid artery graft with end-to-side anastomoses. The vein graft (blue) is sutured to the common carotid artery (red) at two anastomoses. At each anastomosis, stitches (white X&#39;s) are numbered in the order in which they are placed. For both of the anastomoses, stitch 1 sutures the caudal end&#160;of the arteriotomy to the external jugular vein. Stitch 2 sutures the cranial end of the arteriotomy to the external jugular vein. Stitch 3 is placed on the lateral side of the anastomosis at a point equidistant from the first two stitches. Stitch 4 is placed on the medial side of the anastomosis, equidistant from the first two stitches and across from stitch 3. Four additional stitches (stitches 5-8) are placed midway between the four existing stitches. The carotid artery segment between the anastomoses is ligated at both ends with 3-0 silk sutures (arrows) and divided (dashed line) halfway between the ligatures. Left-sided grafts are performed in a similar manner. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57231/57231fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57231/57231fig2.jpg" /> 
Figure 2. The creation and closure of a carotid arteriotomy. (A) The common carotid artery adventitia is grasped near the vein graft with fine forceps and upward traction is applied to the artery wall. This creates a vertical surface, allowing the bent 21 G needle to be inserted approximately parallel to the vessel lumen, decreasing the risk of puncturing the back wall of the artery. (B) The arteriotomy is sutured using 7-0 polypropylene in an X-pattern. The first suture pass enters the artery lumen at the bottom right of the arteriotomy (site 1) and exits the lumen at the bottom left (site 2). The suture then crosses the arteriotomy. The next pass re-enters the lumen at the top right (site 3), and exits the lumen at the top left (site 4). Gentle traction on the ends of the suture (the ends exit from site 1 and site 4) closes the arteriotomy. The suture ends are tied with 2 square knots. The solid blue circles indicate the locations where the suture penetrates the arterial wall. The solid blue lines indicate where the suture passes outside of the arterial wall; dotted blue lines indicate that the suture is located inside the lumen. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57231/57231fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57231/57231fig3.jpg" /> 
Figure 3. Transcutaneous ultrasound images of rabbit necks, evaluating vein graft patency 5-7 days after grafting. (A) Patent vein graft (red) with blood flow in caudal-to-cranial direction is indicated (arrow). (B) Occluded vein graft. No caudal-to-cranial blood flow (which would appear red) is detected. The internal jugular vein (blue) with blood flow in cranial-to-caudal direction is indicated (asterisk). <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57231/57231fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57231/57231fig4.jpg" /> 
Figure 4. Beta-galactosidase transgene expression in vein grafts. 28 days after grafting, rabbit vein grafts were transduced by a 20-min incubation of adenoviral vectors expressing &#946;-galactosidase within the lumens of surgically isolated vein grafts. Vein grafts were harvested 3 days after transduction and stained with 5-bromo-4-chloro-3-indolyl-&#946;-D-galactopyranoside. (A) En face image of the luminal surface of a vein segment showing efficient transduction. (B) En face image of the luminal surface of a vein segment showing poor transduction. Scale bar = 1.0 mm. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57231/57231fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/57231/57231fig5.jpg" /> 
Figure 5. Expression of beta-galactosidase (&#946;-gal) transgene mRNA in vein graft segments. 28 days after the placement of jugular vein interposition grafts in rabbit carotids, the grafts were transduced either with an adenoviral vector expressing beta-galactosidase (AdnLacZ) or with a control adenoviral vector that does not express a transgene (AdNull). Surgeries were completed by either an experienced operator (Surgeon 1) or a new operator (Surgeon 2). Vein grafts transduced with AdnLacZ were all harvested 3 days after transduction. RNA extracted from grafts transduced with AdNull and harvested 14 days after transduction was also analyzed, as a negative control. The expression of beta-galactosidase mRNA was quantified by quantitative reverse transcriptase-mediated PCR, with values normalized to glyceraldehyde phosphate dehydrogenase mRNA measured in the same extracts, and expressed as arbitrary units (AU). Bars indicate mean values; p values are from rank-sum tests. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57231/57231fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about A Rabbit Model of Durable Transgene Expression in Jugular Vein to Common Carotid Artery Interposition Grafts at JoVE.com

A Rabbit Model of Durable Transgene Expression in Jugular Vein to Common Carotid Artery Interposition Grafts

This method describes the placement of interposition vein grafts in rabbits, the transduction of the grafts, and the achievement of durable transgene expression. This allows the investigation of physiological and pathological roles of transgenes and their protein products in grafted veins, and testing of gene therapies for vein graft disease.

Vein graft bypass surgery is a common treatment for occlusive arterial disease; however, long-term success is limited by graft failure due to thrombosis, ...

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Nanyang Technological University

Research

JoVE Journal

Medicine

10.2K Views.  University of Washington School of Medicine. This method describes the placement of interposition vein grafts in rabbits, the transduction of the grafts, and the achievement of durable transgene expression. This allows the investigation of physiological and pathological roles of transgenes and their protein products in grafted veins, and testing of gene therapies for vein graft disease.

Video: A Rabbit Model of Durable Transgene Expression in Jugular Vein to Common Carotid Artery Interposition Grafts

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

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

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

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

Bilateral Common Carotid Artery Occlusion as an Adequate Preconditioning Stimulus to Induce Early Ischemic Tolerance to Focal Cerebral Ischemia

There is accumulating evidence, that ischemic preconditioning - a non-damaging ischemic challenge to the brain - confers a transient protection to a subsequent damaging ischemic insult. We have established bilateral common carotid artery occlusion as a preconditioning stimulus to induce early ischemic tolerance to transient focal cerebral ischemia in C57Bl6/J mice. In this video, we will demonstrate the methodology used for this study.

There is accumulating evidence, that ischemic preconditioning (PC) &#x2013; a non-damaging ischemic challenge to the brain - confers a transient protection to a subsequent damaging ischemic insult. We established bilateral common carotid artery occlusion (BCCAO) as a preconditioning stimulus to induce early ischemic tolerance (IT) to transient focal cerebral ischemia (induced by middle cerebral artery occlusion, MCAO) in C57Bl6/J mice.

There is accumulating evidence, that ischemic preconditioning - a non-damaging ischemic challenge to the brain - confers a transient protection to a ...

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

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

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

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

Catheterization of the Carotid Artery and Jugular Vein to Perform Hemodynamic Measures, Infusions and Blood Sampling in a Conscious Rat Model

The success of a small animal model to study critical illness is, in part, dependent on the ability of the model to simulate the human condition. Intra-tracheal inoculation of a known amount of bacteria has been successfully used to reproduce the pathogenesis of pneumonia which then develops into sepsis. Monitoring hemodynamic parameters and providing standard clinical treatment including infusion of antibiotics, fluids and drugs to maintain blood pressure is critical to simulate routine supportive care in this model but to do so requires both arterial and venous vascular access. The video details the surgical technique for implanting carotid artery and common jugular vein catheters in an anesthetized rat. Following a 72 hr recovery period, the animals will be re-anesthetized and connected to a tether and swivel setup attached to the rodent housing which connects the implanted catheters to the hemodynamic monitoring system. This setup allows free movement of the rat during the study while continuously monitoring pressures, infusing fluids and drugs (antibiotics, vasopressors) and performing blood sampling.

Vascular accesses to measure hemodynamics, provide fluids and perform blood sampling are important to any small animal model study. We present a technique for implanting catheters into the carotid artery and the common jugular vein in an anesthetized rat for connecting to a system to perform monitoring, infusions and sampling.

The success of a small animal model to study critical illness is, in part, dependent on the ability of the model to simulate the human condition. ...

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study model. As the use of mouse models are often a vital step in preclinical drug discovery and drug development1-8, it is necessary to design a system to introduce drugs into mice in a uniform, reproducible manner. Ideally, the system should permit the collection of blood samples at regular intervals over a set time course. The ability to measure drug concentrations by mass-spectrometry, has allowed investigators to follow the changes in plasma drug levels over time in individual mice1, 9, 10. In this study, paclitaxel was introduced into transgenic mice as a continuous arterial infusion over three hours, while blood samples were simultaneously taken by retro-orbital bleeds at set time points. Carotid artery infusions are a potential alternative to jugular vein infusions, when factors such as mammary tumors or other obstructions make jugular infusions impractical. Using this technique, paclitaxel concentrations in plasma and tissue achieved similar levels as compared to jugular infusion. In this tutorial, we will demonstrate how to successfully catheterize the carotid artery by preparing an optimized catheter for the individual mouse model, then show how to insert and secure the catheter into the mouse carotid artery, thread the end of the catheter out through the back of the mouse&#8217;s neck, and hook the mouse to a pump to deliver a controlled rate of drug influx. Multiple low volume retro-orbital bleeds allow for analysis of plasma drug concentrations over time.

This method was developed with the goal of delivering a steady drug solution via the carotid artery, to assess the pharmacokinetics of novel drugs in mouse models.

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study ...

Performing Permanent Distal Middle Cerebral with Common Carotid Artery Occlusion in Aged Rats to Study Cortical Ischemia with Sustained Disability

Stroke typically occurs in elderly people with a range of comorbidities including carotid (or other arterial) atherosclerosis, high blood pressure, obesity and diabetes. Accordingly, when evaluating therapies for stroke in animals, it is important to select a model with excellent face validity. Ischemic stroke accounts for 80% of all strokes, and the majority of these occur in the territory of the middle cerebral artery (MCA), often inducing infarcts that affect the sensorimotor cortex, causing persistent plegia or paresis on the contralateral side of the body. We demonstrate in this video a method for producing ischemic stroke in elderly rats, which causes sustained sensorimotor disability and substantial cortical infarcts. Specifically, we induce permanent distal middle cerebral artery occlusion (MCAO) in elderly female rats by using diathermy forceps to occlude a short segment of this artery. The carotid artery on the ipsilateral side to the lesion was then permanently occluded and the contralateral carotid artery was transiently occluded for 60 min. We measure the infarct size using structural T2-weighted magnetic resonance imaging (MRI) at 24 hr and 8 weeks after stroke. In this study, the mean infarct volume was 4.5% &#177; 2.0% (standard deviation) of the ipsilateral hemisphere at 24 hr (corrected for brain swelling using Gerriet&#8217;s equation, n = 5). This model is feasible and clinically relevant as it permits the induction of sustained sensorimotor deficits, which is important for the elucidation of pathophysiological mechanisms and novel treatments.

Here we present a protocol to produce permanent distal middle cerebral artery occlusion in elderly female rats with simultaneous occlusion of the carotid arteries to generate large cortical infarcts and sustained deficits. We show confirmation of the lesion size using structural MRI at 24 hr and 8 weeks after stroke.

Stroke typically occurs in elderly people with a range of comorbidities including carotid (or other arterial) atherosclerosis, high blood pressure, ...

Vein Interposition Model: A Suitable Model to Study Bypass Graft Patency

Bypass grafting is an established treatment method for coronary artery disease. Graft patency continues to be the Achilles heel of saphenous vein grafts. Research models for bypass graft failure are essential for a better understanding of pathobiological and pathophysiological processes during graft patency loss. Large animal models, such as pigs or sheep, resemble human anatomical structures but require special facilities and equipment. This video describes a rat vein interposition model to investigate vein graft patency loss. Rats are inexpensive and easy to handle. Compared to mouse models, the convenient size of rats permits better operability and enables a sufficient amount of material to be obtained for further diverse analysis. In brief, the inferior epigastric vein of a donor rat is harvested and used to replace a segment of the femoral artery. Anastomosis is conducted via single stitches and sealed with fibrin glue. Graft patency can be monitored non-invasively using duplex sonography. Myointimal hyperplasia, which is the main cause for graft patency loss, develops progressively over time and can be calculated from histological cross sections.

This video demonstrates a model to study the development of myointimal hyperplasia after venous interposition surgery in rats.

Bypass grafting is an established treatment method for coronary artery disease. Graft patency continues to be the Achilles heel of saphenous vein grafts. ...

In Vivo Gene Transfer to the Rabbit Common Carotid Artery Endothelium

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

In Vivo Gene Transfer to the Rabbit Common Carotid Artery Endothelium

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

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

Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery

Phase contrast magnetic resonance imaging (PC-MRI) is a noninvasive approach that can quantify flow-related parameters such as blood flow. Previous studies have shown that abnormal blood flow may be associated with systemic vascular risk. Thus, PC-MRI can facilitate the translation of data obtained from animal models of cardiovascular diseases to pertinent clinical investigations. In this report, we describe the procedure for measuring blood flow in the common carotid artery (CCA) of rats using cine-gated PC-MRI and discuss relevant analysis methods. This procedure can be performed in a live, anesthetized animal and does not require euthanasia after the procedure. The proposed scanning parameters yield repeatable measurements for blood flow, indicating excellent reproducibility of the results. The PC-MRI procedure described in this article can be used for pharmacological testing, pathophysiological assessment, and cerebral hemodynamics evaluation.

The overall goal of this procedure is to measure the blood flow in the rat common carotid artery by using noninvasive phase contrast magnetic resonance imaging.

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

Ferric Chloride-induced Canine Carotid Artery Thrombosis: A Large Animal Model of Vascular Injury

Occlusive arterial thrombosis leading to cerebral ischemic stroke and myocardial infarction contributes to ~13 million deaths every year globally. Here, we have translated a vascular injury model from a small animal into a large animal (canine), with slight modifications that can be used for pre-clinical screening of prophylactic and thrombolytic agents. In addition to the surgical methods, the modified protocol describes the step-by-step methods to assess carotid artery canalization by angiography, detailed instructions to process both the brain and carotid artery for histological analysis to verify carotid canalization and cerebral hemorrhage, and specific parameters to complete an assessment of downstream thromboembolic events by utilizing magnetic resonance imaging (MRI). In addition, specific procedural changes from the previously well-established small animal model necessary to translate into a large animal (canine) vascular injury are discussed.

Here, we present the modifications necessary to a well characterized and commonly used small animal ferric chloride-induced (FeCl3) carotid artery injury model for use in a large animal vascular injury model. The resulting model can be utilized for pre-clinical trial assessment of both prophylactic and thrombolytic pharmacological and mechanical interventions.

Occlusive arterial thrombosis leading to cerebral ischemic stroke and myocardial infarction contributes to ~13 million deaths every year globally. Here, ...