Name: delivery of cardioactive therapeutics in a porcine myocardial infarction model
Uploaded: 2023-02-10T12:40:00
Duration: 7 min 20 s
Description: Watch this Scientific Journal Video about Delivery of Cardioactive Therapeutics in a Porcine Myocardial Infarction Model at JoVE.com

This work was funded by grants from the National Health and Medical Research Council APP1194139/APP1126276 (JC), National Stem Cell Foundation of Australia and New South Wales Government Office of Health and Medical Research (JC). DS was supported by the Royal Australasian College of Physicians, the Institute of Clinical Pathology and Medical Research, and the Australian Government Research Training Program. TD was supported by the Institute of Clinical Pathology and Medical Research, Penfolds Family Scholarship, National Health and Medical Research Council (APP2002783) and the National Heart Foundation of Australia (104615).

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The authors have nothing to disclose.

Transepicardial intramyocardial injection 
This procedure has the benefit of direct cardiac visualization and has been demonstrated to provide greater local retention of therapeutics than systemic administration methods9,10,14. However, thoracotomies are invasive, require considerable technical skill, and present a greater risk of morbidity and mortality than other methods discussed10,15. Knowledge of the critical and precarious stages of the procedure can assist in the mediation of this increased risk.
Great care must be exercised upon manipulating the heart to expose the cardiac apex due to the high risk of arrhythmia and associated hemodynamic compromise. Continuous invasive blood pressure monitoring and electrocardiography allow for rapid identification of hypotension or unstable arrhythmias, facilitating prompt intervention and correction. Transient hypotension can generally be treated with metaraminol boluses. Sustained hypotension may be temporized by reducing inhalant anaesthetic (careful monitoring of anaesthetic depth) and commencing a vasopressor infusion, while concurrently determining the cause of altered hemodynamics. Unstable arrhythmias, such as ventricular tachycardia or ventricular fibrillation, can be treated by electrical cardioversion with or without intravenous antiarrhythmics.
Equally important for animal survival is the successful removal of free gas from the pleural cavity before closing the chest. Failure to do so can culminate in developing a pneumothorax, leaving the animal at great risk of respiratory compromise and death once disconnected from the mechanical ventilator at recovery. Positive airway pressure must be maintained for at least 30 s until bubbling is no longer observed. The silicone tubing is promptly removed upon the cessation of bubbling, and the thorax is then rapidly closed. It is also possible to surgically place a thoracostomy tube at closure, allowing manual air and inflammatory fluid removal over the next 24-72 h. This, however, is difficult to keep clean and intact, especially if animals are housed together. Damage or contamination of the tube can lead to pyothorax, pneumothorax, or sepsis. In our experience, inserting a temporary chest drain is not required if free gas is adequately removed prior to chest closure.
Percutaneous transendocardial intramyocardial injection 
This method of therapeutic administration has the benefit of allowing for local tissue delivery with lower risk due to its less invasive nature compared with a surgical approach10,14. This technique is already used in large animal studies, with both fluoroscopy and electromechanical mapping as a guide in the absence of direct visualization10,16,17.
Given the heart isn&#39;t under direct vision, it is prudent for the proceduralist to use orthogonal fluoroscopic views when selecting an injection site. Furthermore, the injection of diluted iodine contrast before and delivery of the therapeutic is extremely valuable in confirming myocardial contact. Appropriate contact can be confirmed by observing a characteristic &#39;myocardial blush&#39;, which may be one of the only markers of injection success prior to tissue harvest. Due to the risk of chamber perforation, the myocardial wall thickness at the selected injection site is also recommended to be greater than 9 mm14,16.
Jugular venous osmotic minipump 
The osmotic minipump is a popular device commonly employed in small animal studies. There has been increasing interest in using this device in large animal models7,18,19, given its unique advantage of administering a therapeutic agent at a consistent rate over a set time period. A possible limitation of this method is the inability to alter or stop infusion rates of the drug without replacing or removing the pump. This should be considered before trialing therapy in this manner.
This study demonstrated that this method could be performed with a high success rate in swine, with low morbidity and mortality. It must be noted that many vital structures are adjacent to the surgical site, including lymph nodes, the thymus, and the carotid artery. Adherence to the method, and consultation of anatomical texts20, are strongly recommended to prevent inadvertent damage to any of these structures. The most concerning complication of this method is hemorrhagic shock due to inadvertent injury to the jugular vein or a surrounding structure. It is therefore critical that the soft tissue surrounding the jugular vein is carefully removed. Failure to properly complete this step can lead to difficulty in placing the minipump tubing or controlling inadvertent bleeding.
This article has described three methods for the delivery of cardioactive therapeutics. Despite the reported success of each technique, there are inherent limitations to be considered. Invasive procedures (transepicardial injection) allow for increased accuracy of therapeutic delivery; however, they bring a greater risk of potentially fatal complications. Furthermore, invasive delivery has a greater requirement for technical skills to minimize the risk of complications. Similarly, fluoroscopic-guided, transendocardial injection requires a degree of technical skill for catheterization and manipulation of hardware. If this method is performed improperly, injection failure and fatal complications are possible.
The direct injection methods described allow for the one-off administration of a therapeutic into the target tissue. The jugular venous osmotic minipump allows for the systemic administration of a therapeutic over a 7 day period. Comparatively, this method is simpler and associated with less risk, however, it relies on a systemic therapeutic finding its way to the myocardium. Additionally, once the pump is in place, it is impossible to discontinue administration or alter the dose rate without re-anaesthetizing the animal and removing the pump.
All methods described in this article were performed on animals on the day or 2 weeks after myocardial infarction. Therefore, this work cannot report the success of mentioned methods in healthy animals or animals subjected to an alternative cardiac pathology. Finally, the pharmacology and biotechnology of any intended agent are to be carefully considered, as this will be inherently linked to the efficacy of the chosen delivery route. A detailed discussion of this is beyond the scope of this manuscript.
Comprehensive depictions of preclinical methods benefit animal welfare and the wider scientific community. The resultant enhanced reproducibility of procedures and results leads to fewer animal health complications, reduced number of animals required to produce significant results, and greater confidence in experimental outcomes21,22. Three methods of administration of novel therapeutics are described in this article for the treatment of myocardial infarction in a porcine model. By detailing the techniques used and articulating the benefits and risks of each, it is anticipated that researchers will be able to comfortably create consistent and reliable preclinical models that suit their research goals.

Coronary artery disease (CAD) and associated ST-elevation myocardial infarction (STEMI) are the preeminent causes of death worldwide. In the past two decades, great progress has been made in reducing in-hospital mortality of patients presenting with STEMI, through the advent of percutaneous coronary intervention, fibrinolytic therapies, and standardization of treatment algorithms to ensure that reperfusion is achieved in a timely manner1,2,3. Despite this, the morbidity associated with STEMI remains a significant burden, thus creating a great need for developing novel cardioprotective and regenerative therapies2,3. An essential component of therapeutic development is the determination of how a novel therapy is to be administered4. The safety, efficacy, and feasibility of each method need to be matched with the characteristics of the therapy itself.
Physiologically relevant large animal models are critical in assessing these attributes of various therapeutic delivery strategies5. Due to their similarities to humans in cardiovascular physiology, coronary vascular anatomy, and heart weight to body weight ratio, swine is one of the preferred species in the preclinical evaluation of new therapies for myocardial infarction6. We have previously used a porcine STEMI model to demonstrate the reparative capacity of a recombinant protein therapy7, and continue to investigate novel pharmacologic, cellular, and genetic therapies using this model. Here, three techniques of therapeutic administration used in swine models after infarct creation are described: thoracotomy and transepicardial injection, percutaneous transendocardial injection, and jugular venous osmotic minipump implantation. The first two methods enable local tissue delivery, reducing required dosages, off-target effects, and hepatic first-pass metabolism8,9,10. The osmotic minipump allows continuous delivery of a drug with a short half-life, negating reliance on an infusion pump and patent intravenous cannula, both of which are challenging to institute in large animal models.
By describing these techniques, it is hoped that this article can aid translational scientists in investigating novel cardioprotective or regenerative agents following myocardial infarction in large animal models.

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	<tbody>
		<tr>
			<td>Central line placement</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>2-0 sutures</td>
			<td>Ethicon</td>
			<td>JJ9220</td>
			<td></td>
		</tr>
		<tr>
			<td>Arrow&#39; Paediatric Two-Lumen Central Venous Catheterisation Set with Blue FlexTip Catheter (contains 18G cook needle and 0.035&#34; J-tip wire)</td>
			<td>Teleflex</td>
			<td>CS-14502</td>
			<td>Central Line</td>
		</tr>
		<tr>
			<td>Green Fluorsence Protein (GFP)</td>
			<td>Abcam</td>
			<td>ab13970</td>
			<td>1:100 dilution ratio</td>
		</tr>
		<tr>
			<td>Histology antibodies</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ku80</td>
			<td>Cell Signalling Technology</td>
			<td>C48E7</td>
			<td>1:500 dilution ratio</td>
		</tr>
		<tr>
			<td>No. 11 scalpel</td>
			<td>Swann-Morton</td>
			<td>203</td>
			<td></td>
		</tr>
		<tr>
			<td>Sparq&#39; Ultrasound System</td>
			<td>Philips</td>
			<td>MP11742 Medpick</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile ultrasound probe cover</td>
			<td>Atris</td>
			<td>28041947</td>
			<td></td>
		</tr>
		<tr>
			<td>Swine Jacket with Pocket, size &#39;Medium&#39;</td>
			<td>Lomir Biomedical</td>
			<td>SS J2YJJET</td>
			<td></td>
		</tr>
		<tr>
			<td>Jugular vein osmotic minipump implantation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Adson Brown Tissue Forceps</td>
			<td>Icon Medical Supplies</td>
			<td>KLINI316012</td>
			<td></td>
		</tr>
		<tr>
			<td>Bellucci Self-Retaining Retractor</td>
			<td>surgicalinstruments.net.au</td>
			<td>group-24.26.02</td>
			<td>Self retaining tissue retractor</td>
		</tr>
		<tr>
			<td>Electrosurgical Pencils with &#39;Edge&#39; Coated Electrodes</td>
			<td>Covidien</td>
			<td>E2450H</td>
			<td>Cautery Pencil</td>
		</tr>
		<tr>
			<td>Metzenbaum Scissors</td>
			<td>Icon Medical Supplies</td>
			<td>ARMO3250</td>
			<td></td>
		</tr>
		<tr>
			<td>No. 22 scalpel blade</td>
			<td>Swann-Morton</td>
			<td>208</td>
			<td></td>
		</tr>
		<tr>
			<td>Nylon Suture&#160; (2-0, 3-0)</td>
			<td>Ethicon</td>
			<td>D9635, 663G</td>
			<td></td>
		</tr>
		<tr>
			<td>Osmotic Infusion Minipump</td>
			<td>Alzet</td>
			<td>2ML1, 2ML2, 2ML4</td>
			<td></td>
		</tr>
		<tr>
			<td>Vascular Silicone Ties</td>
			<td>Vecmedical</td>
			<td>95001</td>
			<td></td>
		</tr>
		<tr>
			<td>Vicryl suture (5-0)</td>
			<td>Ethicon</td>
			<td>W9982</td>
			<td></td>
		</tr>
		<tr>
			<td>Percutaneous transedocardial injection</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Artis Zee&#39; C-Arm Fluoroscopy&#160;</td>
			<td>Siemens&#160;</td>
			<td>IR-19-1994</td>
			<td></td>
		</tr>
		<tr>
			<td>CARTO&#39; 3 System&#160;&#160;</td>
			<td>Biosense Webster</td>
			<td></td>
			<td>Electrophysiological Mapping Software &#38; System</td>
		</tr>
		<tr>
			<td>Cook Access Needle</td>
			<td>Cook Medical</td>
			<td>G07174</td>
			<td>Cannulation needle</td>
		</tr>
		<tr>
			<td>Fast-Cath&#39; Introducer (6 French, 8 French)</td>
			<td>Abbott</td>
			<td>406204, 406142</td>
			<td>Vascular sheath with introducer and guidewire</td>
		</tr>
		<tr>
			<td>Myostar&#39; Injection Catheter</td>
			<td>Biosense Webster</td>
			<td>121117S, 121119S, 1211120S</td>
			<td>Intramyocardial injection catheter</td>
		</tr>
		<tr>
			<td>No.11 scalpel</td>
			<td>Swann-Morton</td>
			<td>203</td>
			<td></td>
		</tr>
		<tr>
			<td>Omnipaque&#39; Iohexol Contrast</td>
			<td>GE Healthcare</td>
			<td>AUST R 39861&#160;</td>
			<td>Iodinated contrast agent</td>
		</tr>
		<tr>
			<td>Sparq&#39; Ultrasound System</td>
			<td>Philips</td>
			<td>MP11742 Medpick</td>
			<td></td>
		</tr>
		<tr>
			<td>Sedation &#38; general anaesthesia</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Compound Sodium Lactate Hartmann&#39;s Solution</td>
			<td>Free flex</td>
			<td>894451</td>
			<td></td>
		</tr>
		<tr>
			<td>Fentanyl 50 mcg/mL</td>
			<td>Pfizer</td>
			<td>AUST R 107027.</td>
			<td>Intravenous anaesthesia and analgesia</td>
		</tr>
		<tr>
			<td>Forthane&#39; Isoflurane</td>
			<td>Abbott</td>
			<td>AUST R 29656&#160;</td>
			<td>Inhalant anaesthetic</td>
		</tr>
		<tr>
			<td>GE Aestiva 5 Anaesthesia Machine&#160;</td>
			<td>Datex Ohmeda</td>
			<td>17002-9, 17002A9 Avante Health Solutions</td>
			<td>Anaesthetic Machine&#160;</td>
		</tr>
		<tr>
			<td>Hypnovel&#39; Midazolam 5 mg/mL</td>
			<td>Roche</td>
			<td>AUST R 13726</td>
			<td>Sedative</td>
		</tr>
		<tr>
			<td>Intravenous cannula</td>
			<td>BD Angiocath</td>
			<td>381137</td>
			<td>20 gauge cannula</td>
		</tr>
		<tr>
			<td>Ketamil&#39; Ketamine 10 mg/mL</td>
			<td>Ilium</td>
			<td>APVMA number: 51188c&#160;</td>
			<td>Sedative</td>
		</tr>
		<tr>
			<td>Laryngoscope</td>
			<td>Miller</td>
			<td>VDI-6205</td>
			<td></td>
		</tr>
		<tr>
			<td>Medetomidine 1 mg/mL</td>
			<td>Ilium</td>
			<td>APVMA number 64251; ACVM number A10488&#160;</td>
			<td>Sedative</td>
		</tr>
		<tr>
			<td>Metaraminol 10 mg/mL</td>
			<td>Phebra</td>
			<td>AUST R 284784</td>
			<td>Short-acting vasopressor</td>
		</tr>
		<tr>
			<td>Methadone 10 mg/mL</td>
			<td>Ilium</td>
			<td>APVMA number: 63712&#160;</td>
			<td>Sedative, Restricted drug</td>
		</tr>
		<tr>
			<td>Onsetron&#39; Ondansetron 2 mg/mL</td>
			<td>Accord Healthcare</td>
			<td>AUST R 205593&#160;</td>
			<td>Anti-emetic</td>
		</tr>
		<tr>
			<td>Propofol-Lipuro&#39; Propofol 10 mg/mL</td>
			<td>Braun</td>
			<td>AUST R 142906&#160;</td>
			<td>Intravenous anaesthetic</td>
		</tr>
		<tr>
			<td>Pulse Oximeter&#160;</td>
			<td>Meditech</td>
			<td>GVPMT-M3S</td>
			<td>Portable pulse oximeter</td>
		</tr>
		<tr>
			<td>Shiley&#39; Cuffed Basic Endotracheal Tube (Size 5.5 &#38; 6.0)</td>
			<td>Medtronic</td>
			<td>86108-, 86109-</td>
			<td></td>
		</tr>
		<tr>
			<td>Shiley&#39; Intubating Stylet, 10 Fr</td>
			<td>Medtronic</td>
			<td>85864</td>
			<td></td>
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		<tr>
			<td>Sodium Chloride 0.9%</td>
			<td>Free flex</td>
			<td>FAH1322</td>
			<td></td>
		</tr>
		<tr>
			<td>Thoracotomy and epicardial Cell Injection</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>27 G Insulin needle</td>
			<td>Terumo</td>
			<td>51907</td>
			<td></td>
		</tr>
		<tr>
			<td>Adson Brown Tissue Forceps</td>
			<td>Icon Medical Supplies</td>
			<td>KLINI316012</td>
			<td></td>
		</tr>
		<tr>
			<td>CARTO&#39; 3 System&#160;&#160;</td>
			<td>Biosense Webster</td>
			<td></td>
			<td>Electrophysiological Mapping Software &#38; System</td>
		</tr>
		<tr>
			<td>Cefazolin 1 g Vial</td>
			<td>AFT Pharmaceuticals</td>
			<td>9421900137367 CH2</td>
			<td>Antibiotic Prophylaxis&#160;</td>
		</tr>
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			<td>Chest drainage tube</td>
			<td>SurgiVet</td>
			<td>SKU-336</td>
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			<td>Cook Access Needle</td>
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			<td>Cannulation needle</td>
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			<td>Millennium Surgical</td>
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			<td>Janssen</td>
			<td>AUST R 112371&#160;</td>
			<td>Postoperative analgesia</td>
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		<tr>
			<td>Electrosurgical Pencils with &#39;Edge&#39; Coated Electrodes</td>
			<td>Covidien</td>
			<td>E2450H</td>
			<td>Cautery Pencil</td>
		</tr>
		<tr>
			<td>Electrosurgical Pencils with &#39;Edge&#39; Coated Electrodes</td>
			<td>Covidien</td>
			<td>E2450H</td>
			<td>Cautery Pencil</td>
		</tr>
		<tr>
			<td>Fast-Cath&#39; Introducer (6 French, 8 French)</td>
			<td>Abbott</td>
			<td>406204, 406142</td>
			<td>Vascular sheath with introducer and guidewire</td>
		</tr>
		<tr>
			<td>Lignocaine 20 mg/mL</td>
			<td>Pfizer</td>
			<td>AUST R 49296, AUST R 49297, AUST R 49293 and AUST R 49295.</td>
			<td>Local anaesthesia, anti-arrhythmic</td>
		</tr>
		<tr>
			<td>Marcaine&#39; Bupivacaine 0.5%</td>
			<td>Pfizer</td>
			<td>AUST R 48328&#160;</td>
			<td>Local anaesthesia.&#160;</td>
		</tr>
		<tr>
			<td>Metzenbaum Scissors</td>
			<td>Icon Medical Supplies</td>
			<td>ARMO3250</td>
			<td></td>
		</tr>
		<tr>
			<td>No. 22 scalpel</td>
			<td>Swann-Morton</td>
			<td>208</td>
			<td></td>
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			<td>Nylon Suture&#160; (2-0, 3-0)</td>
			<td>Ethicon</td>
			<td>D9635, JJ76264</td>
			<td></td>
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			<td>Size 1 PDS suture</td>
			<td>Ethicon</td>
			<td>JJ75414</td>
			<td></td>
		</tr>
		<tr>
			<td>Sparq&#39; Ultrasound System</td>
			<td>Philips</td>
			<td>MP11742 Medpick</td>
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			<td>Sterile gauze</td>
			<td>Kerlix</td>
			<td>KE5072</td>
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			<td>Sterile laparotomy sponges</td>
			<td>Propax</td>
			<td>2907950</td>
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			<td>Thermocool Smartouch&#39; Catheter</td>
			<td>Biosense Webster</td>
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			<td>Epicardial Mapping Catheter</td>
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</table>

delivery of cardioactive therapeutics in a porcine myocardial infarction model

Myocardial infarction is one of the leading causes of death and disability worldwide, and there is an urgent need for novel cardioprotective or regenerative strategies. An essential component of drug development is determining how a novel therapeutic is to be administered. Physiologically relevant large animal models are of critical importance in assessing the feasibility and efficacy of various therapeutic delivery strategies. Due to their similarities to humans in cardiovascular physiology, coronary vascular anatomy, and heart weight to body weight ratio, swine is one of the preferred species in the preclinical evaluation of new therapies for myocardial infarction. The present protocol describes three methods of administering cardioactive therapeutic agents in a porcine model. After percutaneously induced myocardial infarction, female landrace swine received treatment with novel agents through either: (1) thoracotomy and transepicardial injection, (2) catheter-based transendocardial injection, or (3) intravenous infusion via jugular vein osmotic minipump. The procedures employed for each technique are reproducible, resulting in reliable cardioactive drug delivery. These models can be easily adapted to suit individual study designs, and each of these delivery techniques can be used to investigate a variety of possible interventions. Therefore, these methods are a useful tool for translational scientists pursuing novel biological approaches in cardiac repair following myocardial infarction.

Thoracotomy and epicardial cell injection 
Of the 29 animals that underwent thoracotomy and epicardial injection, 26 survived. Histological analysis confirmed the engraftment of human cells delivered by this method in all surviving animals (Figure 1E). One animal experienced fatal arrhythmias during cell injection and could not be resuscitated. Another experienced pulseless electrical activity during closure and prolonged application of positive pressure to the airways and was unable to be recovered. A third animal both vomited and went into respiratory arrest upon extubation. This animal was unable to be resuscitated.
Two animals experienced major complications but were able to be recovered. One animal developed ventricular fibrillation during intramyocardial injection and was able to be resuscitated with internal defibrillation paddles and cardiac massage. The second animal vomited upon extubation and had a brief respiratory arrest but was able to be rapidly re-intubated and recovered well. All of these events occurred during early experiments, with reduced adverse events as team experience with the protocol increased (Table 1).
Jugular vein osmotic minipump implantation 
No reported mortality or major complications were associated with jugular osmotic minipump implantation. Most of the seven animals experienced mild swelling at the surgical site within the first 24 h, which resolved without intervention. ELISA performed on serum on day 3 post-pump implantation demonstrated the efficacy of the pump, achieving a significant blood concentration of platelet-derived growth factor-AB human (PDGF-AB) compared to controls7 (Figure 2E).
Percutaneous transendocardial injection 
A total of 22 animals received endocardial injections. Of these injections, 17 were considered &#39;successful&#39;, determined by fluorescence or ink staining observed in the target tissue at post-mortem (Figure 3B). There were no mortalities associated with this procedure. One animal developed a small volume pericardial effusion from right ventricular perforation. This was self-limiting and did not result in cardiovascular compromise. This same animal did die; however, this was from an unrelated additional procedure after the intramyocardial injection.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/64177/64177fig01.jpg" /> 
Figure 1:&#160;Transepicardial cardiomyocyte injection allows for direct cardiac visualization and achieves a high proportion of viable cells delivered to the myocardium. (A) The cardiac apex is exposed through a moistened gauze sling guided under the base of the heart. (B) An epicardial mapping catheter delineates scar and border zones and annotates injection sites. (C) A 31 G needle is used to transepicardially inject cells into the myocardium. (D) Epicardial voltage map with injection site annotation. Purple: normal voltage, healthy myocardium; Red: abnormal voltage, diseased myocardium; Grey dots: injection sites. Following sacrifice, the heart is collected and formalin-fixed for downstream histological assessment. In (E), engrafted human cells are detected by immunostaining for the human anti-nuclear antibody, Ku80, and an anti-GFP antibody. Scale bar = 200 &#181;m. <a href="https://www.jove.com/files/ftp_upload/64177/64177fig01large.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/64177/64177fig02.jpg" /> 
Figure 2: Jugular vein minipump insertion provides a safe and reliable method of PDGF delivery over a 7 day time period. (A) The right jugular vein is exposed, and soft tissue is cleared away from the vessel. (B) Vascular ties occlude the vessel while a 14 G needle is used to make a puncture, through which the minipump tubing is threaded. (C) The minipump tubing is advanced into the vein, and the minipump body is secured to adjacent soft tissue. (D) The minipump body and tubing prior to implantation. (E) The serum concentration of the recombinant protein delivered via the minipump and the PDGF-AB was measured using ELISA from each animal on day 3 post-implantation. Animals receiving PDGF-AB were demonstrated to have a significantly higher blood concentration of PDGF-AB than control animals, confirming the efficacy of the osmotic minipump administration method. **denotes a statistically significant difference between groups (p = 0.005, Mann-Whitney U test) <a href="https://www.jove.com/files/ftp_upload/64177/64177fig02large.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/64177/64177fig03.jpg" /> 
Figure 3:&#160;Transendocardial intramyocardial injection allows for a minimally-invasive therapeutics administration method. (A) A right anterior oblique fluoroscopic image demonstrating the injection catheter (white arrow) administering contrast material (yellow arrow) into the myocardium. The contrast material injection both precedes and follows therapeutic injection so that needle placement within the myocardium can be confirmed. (B) The injected vector expressed green fluorescent protein (GFP) so that injected material would fluoresce upon tissue collection, thus confirming the success of the injection. <a href="https://www.jove.com/files/ftp_upload/64177/64177fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td></td>
			<td>Transepicardial Injection (n = 29)</td>
			<td>Transendocardial Injection (n = 22)</td>
			<td>Osmotic Minipump (n = 7)</td>
		</tr>
		<tr>
			<td>Mortality&#160;</td>
			<td>3</td>
			<td>0</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Post-operative vomiting and respiratory arrest</td>
			<td>1</td>
			<td>0</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Ventricular Fibrillation during injection</td>
			<td>1</td>
			<td>0</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Pulseless electrical activity during chest closure</td>
			<td>1</td>
			<td>0</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Morbidity</td>
			<td>0</td>
			<td>1</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Pneumothorax</td>
			<td>0</td>
			<td>0</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Pleural effusion</td>
			<td>0</td>
			<td>0</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Cardiac chamber perforation</td>
			<td>0</td>
			<td>1</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Hemorrhage</td>
			<td>0</td>
			<td>0</td>
			<td>0</td>
		</tr>
	</tbody>
</table>
Table 1:&#160;Complications list.

Watch this Scientific Journal Video about Delivery of Cardioactive Therapeutics in a Porcine Myocardial Infarction Model at JoVE.com

Delivery of Cardioactive Therapeutics in a Porcine Myocardial Infarction Model

The present protocol describes three methods of administering cardioactive therapeutic agents in a porcine model. Female landrace swine received treatment through either: (1) thoracotomy and transepicardial injection, (2) catheter-based transendocardial injection, or (3) intravenous infusion via jugular vein osmotic minipump.

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