Name: long-term catheterization of the intestinal lymph trunk and collection of lymph in neonatal pigs
Uploaded: 2016-03-05T14:00:00.000+00:00
Duration: 6 min 25 s
Description: Watch this Scientific Journal Video about Long-Term Catheterization of the Intestinal Lymph Trunk and Collection of Lymph in Neonatal Pigs at JoVE.com

The work was supported in part by funding from Alberta Livestock and Meat Agency and Natural Science and Research Council Discovery grant to S. D. Proctor.

All procedures on experimental animals described in both the video and manuscript were approved by the Institutional Animal Care and Use Committee and followed the guidelines set by the Canadian Council of Animal Care.
1. Surgical Anesthesia and Surgical Preparation of the Neonatal Pigs
<ol>
	<li>In a separated anteroom, premedicate 25 kg pigs near the base of the neck with an intramuscular sedative-anesthetic drug cocktail containing: azaperone (0.3 mg/kg), ketamine hydrochloride (10 mg/kg), dexmedetomidine (15 &#181;g/kg). 
	Note: Add buprenorphine (0.005-0.02 mg/kg) in the pre-anesthetic drug cocktail for enhanced intra-operative pain control.</li>
	<li>Anesthetize the pigs with inhaled isoflurane inhalation gas (4-5% isoflurane at 500 ml-1,000 ml/min O2) using a face mask. Visualize the vocal cords using a veterinary laryngeal scope (17-25 cm long straight blade), and apply topical 10% lidocaine spay to the vocal cords. Allow the lidocaine spray to contact the vocal cords 30-60 sec prior to intubation to reduce the possibility of vocal cord spasm and airway obstruction.</li>
	<li>Intubate the pigs by passing a cuffed endotracheal tube (5.0-7.0 mm Internal Diameter (ID)) between the vocal cords and maintain the anesthesia with isoflurane gas (0.5-2.0% isoflurane at 1,000-2,000 ml/min O2) using a closed circuit rebreathing anesthetic system throughout the surgery. Assess the level of anesthesia by jaw tone, and both pedal and palpebral reflex responses. Expired anesthetic gas is scavenged and vented outside the surgical suite.</li>
	<li>Clean the exterior surface of the ear with 2.0% chlorhexidine surgical scrub solution followed by a 70% isopropyl alcohol rinse. With a 20 G intravenous catheter, catheterize an ear vein to provide intravenous fluids (Lactated Ringer&#39;s Solution; 5-10 ml/kg/hr) during the surgery. Secure a pulse oximeter to the mucosal surface of the tongue with medical tape to monitor heart rate and the saturation of peripheral blood oxygenation (SpO2).</li>
	<li>Place the anesthetized pig in a dorsal recumbent position and shave the ventral abdomen from the mid thorax caudally to the ventral aspect of the pubis. Clean this area with two alternating 2.0 % chlorhexidine surgical scrubs and sterile water washes.</li>
	<li>Transfer the anaesthetized pig to the surgical suite and apply the final surgical scrub of 70% isopropyl alcohol rinse, allow it to dry, and then drape the animal.</li>
	<li>Insert a rectal temperature probe approximately 2-4 cm into the rectum to monitor body temperature. Place the pigs on a water recirculating heating pad to maintain normal body temperature (38-40 &#176;C) during surgical procedure.</li>
	<li>Drape the pig with four towels drapes placed in an overlying quadrant pattern around the abdomen. Place the first drape across xiphisternum, the second drape along lateral aspect of the abdomen approximately 5 cm lateral to the abdominal midline. Place the third drape across the ileal crest of the pelvis and the fourth drape, like the second drape (although on the opposite side), is placed along the lateral aspect of the abdomen approximately 5 cm lateral to the abdominal midline.</li>
	<li>Place a large table drape, with a slit-opening allowing access to the surgical site, over the underlying towel drapes and cover the pig and entire surgical table. The final drape is a disposable steri-drape placed over the large table drape.</li>
</ol>
2. Abdominal Surgery and Catheterization of the Intestinal Lymphatic Trunk
<ol>
	<li>Make a 20 cm skin incision with a scalpel blade to expose the underlying abdominal muscles. Incise the abdominal muscle layers with mono-polar electrocautery (20 Watts setting) to expose the parietal peritoneum. Open a 20 cm linear segment of parietal peritoneum with Metzenbaum scissors to access the abdominal viscera and lymphatic vessel.</li>
	<li>Place a retractor at the cranial aspect of the surgical incision to keep the abdominal cavity open for the duration of the surgery.</li>
	<li>Moisten all tissues with warm (37 &#176;C) sterile saline for the entire surgical procedure. Gently lift a large segment of intestine including the colon, cecum, ileum and jejunum from the abdominal cavity and exteriorize it to the left flank of the pig to access the upper abdomen, liver and lymphatic vessel. Secure the exteriorized intestine in position with additional towel drapes to form a sling to gently support the intestine.</li>
	<li>Locate the lymphatic vessel, it lays approximately 4 cm cranial-medial of the right renal vein, 6 cm caudal-medial- ventral of the caval foremen and underneath the visceral aspect of the right liver lobe near the pancreas22,36,37. Identify the lymphatic vessel as a translucent structure juxtaposed to the right ventral segment of the portal vein36,37.</li>
	<li>Separate the lymphatic vessel from the surrounding fascia by gently teasing away the attached tissue with Q-tip applicators. Once the lateral aspects of vessel are separated from the surrounding tissue, create a &#34;tunnel&#34; opening underneath the vessel with fine blunt tipped forceps.</li>
	<li>Pass three 2-0 silk sutures underneath the lymphatic vessel with fine forceps. Ligate the most caudal suture first to occlude, dilate and fill the vessel with lymph. Purposefully leave the ends of this suture relatively long (4 cm) to secure the catheter to the lymphatic vessel. Place two other sutures separated 1.0 cm from each other and are approximately 1.0-1.5 cm cranial to the secured caudal suture. Leave these two sutures with a &#39;single loose ligature tie&#39; to allow for faster securing of the catheter into the vessel. 
	Note: The segment of the lymphatic vessel located between the most caudal ligating suture and middle suture (of the two cranial sutures) is the site for catheterization. Regarding suture material, 2-0 polyglactin suture can substitute for 2-0 silk sutures if required.</li>
	<li>Cut a small hole into the vessel with iris scissors and dilate the vessel with fine blunt forceps. Insert approximately 1.0-1.5 cm of specialized catheter tubing (4.06 Outer Diameter (OD) X 2.31 mm ID) with a beveled end into the vessel and tie the two cranial sutures to secure the catheter in place. Use the long suture ends of the caudal suture to secure the catheter to the vessel.</li>
	<li>Wash the exteriorized intestine with copious amounts of warm saline and gently return it to the abdominal cavity ensuring correct anatomical positioning of the gut.</li>
	<li>Exteriorize the catheter at the left mid flank (5-10 cm ventrally from the paralumbar fossa). Make a skin incision with a scalpel and pass a trocar from the abdominal cavity to the skin surface to create an opening for the exteriorization of the catheter. Use a large Kelly forceps to exteriorize the catheter from the abdominal cavity through the trocar opening.</li>
	<li>Close the parietal peritoneum with a simple continuous suture pattern of 2-0 polyglactin suture with a round (tapered) needle. Close the abdominal muscle layers with a simple interrupted suture pattern with a 2-0 polyglactin suture on a round needle.</li>
	<li>Close the skin in a subcuticular pattern with 2-0 polyglactin suture on a cutting needle. Secure the exteriorized catheter to the skin with a purse-string suture pattern and a 2-0 nylon suture on a cutting needle.</li>
	<li>Place a specialized jacket on the pig while still anesthetized to ease its placement and reduce the stress of the pig during recovery.</li>
</ol>
3. Post-surgical Recovery and Lymph Collection
<ol>
	<li>Approximately 10 min prior to the discontinuation of inhalation anesthesia, administer bupenorphine (0.1 mg/kg) intramuscularly to provide immediate post-surgery analgesia. Continue bupenorphine (0.1 mg/kg) every 12 hr for 24-48 hr to maintain post-surgery analgesia.</li>
	<li>Monitor the pigs for post-surgical complications every 8-12 hr for a 7 day period.</li>
	<li>Collect the lymph in 500 ml polypropylene wash bottles, coated with ethylenediamine tetraacetic acid (EDTA), and supplemented with antibiotics; penicillin (6,000 IU), streptomycin (6 mg) and amphotericin B (3 mg) every 12 hr for a 7 day period.</li>
</ol>
4. Quantification of Lipoprotein ApoB48, Triglyceride, Cholesterol and Total Protein Collected from Lymph
<ol>
	<li>Centrifuge the lymph sample at 1,800 x g for 5 min at 4 &#176;C. Collect the supernatant and use it for the quantification of triglyceride, cholesterol and total protein.</li>
	<li>Divide the supernatant into three samples: an undiluted sample, a sample diluted 1:20 distilled water and a final sample diluted 1:100 with distilled water.</li>
	<li>Use the undiluted supernatant to measure cholesterol levels, with a commercially available kit.</li>
	<li>Use the 1:20 and 1:100 diluted samples to measure triglyceride and total protein levels with a commercially available kit and the bicinchoninic acid-total protein assay respectively.</li>
</ol>
5. Quantification of Lipoprotein ApoB48, Collected from Lymph38
<ol>
	<li>Determine the concentration of lipoprotein ApoB48 with an adapted immune Western Blotting method38. Separate total lymph with 3-8% tris-acetate- sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).</li>
	<li>Transfer the separated proteins to a polyvinylidene fluoride membrane (0.45 &#181;m) and incubate them with a goat polyclonal antibody to ApoB (1:4,000), then bind it with an anti-goat secondary antibody.</li>
	<li>Quantify the lipoprotein ApoB48 with chemiluminescence using a linear densitometric comparison with purified rodent ApoB48 protein standard.</li>
</ol>

The authors have nothing to disclose.

Collecting intestinal lymph is an excellent method to investigate mechanisms involved in lipid8-12 and drug13-15 metabolism, cancer metastasis16,17, cell trafficking and immune function18-26, in various experimental animal models. Indeed, the ability to harvest large quantities of either peripheral (afferent) and central (efferent and large trunk vessels) lymph over an extended period has been particularly important for understanding temporal changes that occur in cell populati...

The lymphatic system is an understudied area of physiology. Preclinical models of lymphatic catheterization occur in different animal species1-8 and are used by pharmaceutical industries and research institutions to investigate mechanisms involved in lipid8-12 and drug metabolism13-15, cancer metastasis16 with experimental treatment17, and immune function18-26. This study explores the use of intestinal lymph trunk catheterization in a domestic pig model to measure components of lipoprotein metabolism. Lipoprotein metabolism is involved in the production and secretion of chylomicrons, as well as changes in associated lipids and total protein. These are important considerations as there are major differences in lipid metabolism between commonly used rodent models and humans and as such, employing swine models to collect intestinal lymph could provide more comparable information for studying lipid metabolism in people27-31.
Several surgical techniques are used to collect the intestinal lymph in large animal species: a cranial shoulder approach (i.e., thoracic duct catheterization)5, a lateral upper flank approach32-34, and a ventral midline or paramedian approach22,35. This video describes in detail the surgical procedure in swine using a ventral midline surgical approach for the catheterization of the intestinal lymph trunk. Careful surgical technique permits this method of lymphatic catheterization to collect large quantities of lymph and its constituents over extended periods of time.
This technique opens a myriad of applications to many disciplines examining various physiologic functions. Applications could include, but are not limited to, whole body lipoprotein and lipid metabolism, immunosurveillance, tumor genesis and metastasis, intestinal function, and the development and progression of intestinal inflammatory disease.

<table><tbody><tr><td>Miller laryngoscope blade</td><td>Welch Allyn</td><td>68044</td><td>182 mm length</td></tr><tr><td>Surgivet advisor: Vital signs monitor</td><td>Surgivet</td><td>V9203</td><td></td></tr><tr><td>Rectal temperature probe</td><td>Surgivet</td><td>V3417</td><td></td></tr><tr><td>Mono-polar electrosurgery generator</td><td>Valley Lab</td><td></td><td></td></tr><tr><td>Metzenbaum scissors</td><td>Fine Science</td><td>14518-18</td><td></td></tr><tr><td>Tuffier retractor</td><td>Stevens</td><td>162-11-676</td><td></td></tr><tr><td>Mosquito forceps</td><td>Stevens</td><td>162-7-10</td><td></td></tr><tr><td>Kelly forceps-curved (14cm)</td><td>Stevens</td><td>162-7-38</td><td></td></tr><tr><td>Allis tissue forceps</td><td>Stevens</td><td>162-7-38</td><td></td></tr><tr><td>Forceps dressing-eye (10.2cm)</td><td>Stevens</td><td>162-18-780</td><td></td></tr><tr><td>Forceps dressing-Adison (12.1cm)</td><td>Stevens</td><td>162-17-2510</td><td></td></tr><tr><td>Needle Drivers</td><td>Stevens</td><td>162-V98-42</td><td></td></tr><tr><td>Iris scissors</td><td>Fine science</td><td>14058-11</td><td></td></tr><tr><td>Circulating water pump</td><td>Jorvet</td><td>J-783X</td><td></td></tr><tr><td>Maxitherm-Vinyl blanket</td><td>Jorvet</td><td>J-784C</td><td></td></tr><tr><td>Q tip applicators</td><td>Fisher Scientific</td><td>22-037-960</td><td></td></tr><tr><td>Catheterization&amp;nbsp; tubing (4.06 OD X 2.31 ID)</td><td>Braintree Scientific Inc.</td><td>MRE-160</td><td>Micro-Renethane implantation tubing</td></tr><tr><td>2-0 silk suture</td><td>Ethicon</td><td>LA556</td><td></td></tr><tr><td>2-0 polyglactin suture</td><td>Ethicon</td><td>J443H</td><td>2-0 vicryl</td></tr><tr><td>Large animal jacket</td><td>Lomir Biomedical Inc.</td><td>SSJ2YC</td><td></td></tr><tr><td>Polypropylene wash bottles</td><td>Fisher Scientific</td><td>03-409-22C</td><td>500 ml</td></tr><tr><td>Penicillin-Streptomycin</td><td>Sigma Aldrich</td><td>D4333</td><td></td></tr><tr><td>EDTA</td><td>Sigma Aldrich</td><td>60-00-4</td><td></td></tr><tr><td>Amphotericin B</td><td>Sigma Aldrich</td><td>A2411</td><td></td></tr><tr><td>Azaperone</td><td>Elanco Animal Health</td><td></td><td>Stresnil</td></tr><tr><td>Dexmedetomidine hydrochloride</td><td>Zoetis</td><td>6295</td><td>Dexdomitor</td></tr><tr><td>Isoflurane</td><td>Abbott Animal&amp;nbsp; Health</td><td>05260-5</td><td>IsoFlo</td></tr><tr><td>Ketamine hydrochloride</td><td>Zoetis</td><td>2626</td><td>Ketaset</td></tr><tr><td>Bupenorphine hydrochloride</td><td>Champion Alstoe Animal Health</td><td></td><td>DIN:02347510</td></tr><tr><td>6 mm Endotracheal tube</td><td>Jorvet</td><td>J-165d</td><td></td></tr><tr><td>10% Lidocaine spray</td><td>AstraZeneca</td><td></td><td>DIN:02003767</td></tr><tr><td>4 % Chlorhexidine surgical scrub</td><td>Partnar Animal Health</td><td>PCH-011</td><td>Diluted: 2.0% solution</td></tr><tr><td>3M Surgical steri- drape</td><td>3M Health Care</td><td>1040</td><td></td></tr><tr><td>SDS page gel</td><td>Invitrogen</td><td>EA0375BOX</td><td>3-8 % tris acetate</td></tr><tr><td>Polyvinylidene fluoride membrane</td><td>Millipore</td><td>IPVH00010</td><td>0.45 &amp;mu;m pore size</td></tr><tr><td>ApoB antibody&amp;nbsp;</td><td>EMD Millipore</td><td>AB742</td><td>1:4000 dilution</td></tr><tr><td>Donkey anti-goat IgG-HRP</td><td>Santa Cruz Biotechnology</td><td>Sc-2304</td><td></td></tr><tr><td>ECL Prime Western Blotting Reagent</td><td>GE Healthcare LifeSciences</td><td>RPN2232&amp;nbsp;&amp;nbsp;&amp;nbsp;</td><td></td></tr><tr><td>Triglyceride Kit</td><td>Wako Pure Chemicals</td><td>998-40391/994-40491</td><td></td></tr><tr><td>Total Cholesterol Kit</td><td>Wako Pure Chemicals</td><td>439-17501</td><td></td></tr><tr><td>Total Protein</td><td>&amp;nbsp;Pierce&amp;nbsp;</td><td>23225</td><td>Bicinchoninic Acid Assay</td></tr></tbody></table>

long-term catheterization of the intestinal lymph trunk and collection of lymph in neonatal pigs

Catheterization of the intestinal lymph trunk in neonatal pigs is a technique allowing for the long-term collection of large quantities of intestinal (central) efferent lymph. Importantly, the collection of central lymph from the intestine enables researchers to study both the mechanisms and lipid constitutes associated with lipid metabolism, intestinal inflammation and cancer metastasis, as well as cells involved in immune function and immunosurveillance. A ventral mid-line surgical approach permits excellent surgical exposure to the cranial abdomen and relatively easy access to the intestinal lymph trunk vessel that lies near the pancreas and the right ventral segment of the portal vein underneath the visceral aspect of the right liver lobe. The vessel is meticulously dissected and released from the surrounding fascia and then dilated with sutures allowing for insertion and subsequent securing of the catheter into the vessel. The catheter is exteriorized and approximately 1 L/24 hr of lymph is collected over a 7 day period. While this technique enables the collection of large quantities of central lymph over an extended period of time, the success depends on careful surgical dissection, tissue handling and close attention to proper surgical technique. This is particularly important with surgeries in young animals as the lymph vessels can easily tear, potentially leading to surgical and experimental failure. The video demonstrates an excellent surgical technique for the collection of intestinal lymph.

Lymphatic catheterization of the intestinal lymphatic trunk of neonatal pigs allows collection of approximately 1 L/24 hr of central lymph over a 7 day period. The lymph collected in this experiments contained components of lipid metabolism, namely total lymph protein, ApoB48 lipoprotein, triglycerides, total protein, and cholesterol. Table 1 highlights representative amounts of these lipid components from pooled lymph samples of three pigs. Notably, lymph flow and lipid constituents are ...

Watch this Scientific Journal Video about Long-Term Catheterization of the Intestinal Lymph Trunk and Collection of Lymph in Neonatal Pigs at JoVE.com

Long-Term Catheterization of the Intestinal Lymph Trunk and Collection of Lymph in Neonatal Pigs

We present a surgical procedure to catheterize the intestinal lymph trunk in neonatal pigs to collect large quantities of lipid metabolism components from efferent lymph.

Catheterization of the intestinal lymph trunk in neonatal pigs is a technique allowing for the long-term collection of large quantities of intestinal ...

long-term-catheterization-intestinal-lymph-trunk-collection-lymph

Universidad de Cartagena UDEC

Research

JoVE Journal

Medicine

8.8K Views.  University of Alberta. We present a surgical procedure to catheterize the intestinal lymph trunk in neonatal pigs to collect large quantities of lipid metabolism components from efferent lymph.

Video: Long-Term Catheterization of the Intestinal Lymph Trunk and Collection of Lymph in Neonatal Pigs

Multispectral Real-time Fluorescence Imaging for Intraoperative Detection of the Sentinel Lymph Node in Gynecologic Oncology

The prognosis in virtually all solid tumors depends on the presence or absence of lymph node metastases.1-3 Surgical treatment most often combines radical excision of the tumor with a full lymphadenectomy in the drainage area of the tumor. However, removal of lymph nodes is associated with increased morbidity due to infection, wound breakdown and lymphedema.4,5 As an alternative, the sentinel lymph node procedure (SLN) was developed several decades ago to detect the first draining lymph node from the tumor.6 In case of lymphogenic dissemination, the SLN is the first lymph node that is affected (Figure 1). Hence, if the SLN does not contain metastases, downstream lymph nodes will also be free from tumor metastases and need not to be removed. The SLN procedure is part of the treatment for many tumor types, like breast cancer and melanoma, but also for cancer of the vulva and cervix.7 The current standard methodology for SLN-detection is by peritumoral injection of radiocolloid one day prior to surgery, and a colored dye intraoperatively. Disadvantages of the procedure in cervical and vulvar cancer are multiple injections in the genital area, leading to increased psychological distress for the patient, and the use of radioactive colloid.
Multispectral fluorescence imaging is an emerging imaging modality that can be applied intraoperatively without the need for injection of radiocolloid. For intraoperative fluorescence imaging, two components are needed: a fluorescent agent and a quantitative optical system for intraoperative imaging. As a fluorophore we have used indocyanine green (ICG). ICG has been used for many decades to assess cardiac function, cerebral perfusion and liver perfusion.8 It is an inert drug with a safe pharmaco-biological profile. When excited at around 750 nm, it emits light in the near-infrared spectrum around 800 nm. A custom-made multispectral fluorescence imaging camera system was used.9.
The aim of this video article is to demonstrate the detection of the SLN using intraoperative fluorescence imaging in patients with cervical and vulvar cancer. Fluorescence imaging is used in conjunction with the standard procedure, consisting of radiocolloid and a blue dye. In the future, intraoperative fluorescence imaging might replace the current method and is also easily transferable to other indications like breast cancer and melanoma.

Fluorescence imaging is a promising innovative modality for image-guided surgery in surgical oncology. In this video we describe the technical procedure for detection of the sentinel lymph node using fluorescence imaging as showcased in gynecologic oncologicy. A multispectral fluorescence camera system, together with the fluorescent agent indocyanine green, is applied.

The prognosis in virtually all solid tumors depends on the presence or absence of lymph node metastases.1-3 Surgical treatment most often combines radical ...

A Swine Model of Neonatal Asphyxia

Annually more than 1 million neonates die worldwide as related to asphyxia. Asphyxiated neonates commonly have multi-organ failure including hypotension, perfusion deficit, hypoxic-ischemic encephalopathy, pulmonary hypertension, vasculopathic enterocolitis, renal failure and thrombo-embolic complications. Animal models are developed to help us understand the patho-physiology and pharmacology of neonatal asphyxia. In comparison to rodents and newborn lambs, the newborn piglet has been proven to be a valuable model. The newborn piglet has several advantages including similar development as that of 36-38 weeks human fetus with comparable body systems, large body size (&tilde;1.5-2 kg at birth) that allows the instrumentation and monitoring of the animal and controls the confounding variables of hypoxia and hemodynamic derangements.
We here describe an experimental protocol to simulate neonatal asphyxia and allow us to examine the systemic and regional hemodynamic changes during the asphyxiating and reoxygenation process as well as the respective effects of interventions. Further, the model has the advantage of studying multi-organ failure or dysfunction simultaneously and the interaction with various body systems. The experimental model is a non-survival procedure that involves the surgical instrumentation of newborn piglets (1-3 day-old and 1.5-2.5 kg weight, mixed breed) to allow the establishment of mechanical ventilation, vascular (arterial and central venous) access and the placement of catheters and flow probes (Transonic Inc.) for the continuously monitoring of intra-vascular pressure and blood flow across different arteries including main pulmonary, common carotid, superior mesenteric and left renal arteries. Using these surgically instrumented piglets, after stabilization for 30-60 minutes as defined by Z&lt;10% variation in hemodynamic parameters and normal blood gases, we commence an experimental protocol of severe hypoxemia which is induced via normocapnic alveolar hypoxia. The piglet is ventilated with 10-15% oxygen by increasing the inhaled concentration of nitrogen gas for 2h, aiming for arterial oxygen saturations of 30-40%. This degree of hypoxemia will produce clinical asphyxia with severe metabolic acidosis, systemic hypotension and cardiogenic shock with hypoperfusion to vital organs. The hypoxia is followed by reoxygenation with 100% oxygen for 0.5h and then 21% oxygen for 3.5h. Pharmacologic interventions can be introduced in due course and their effects investigated in a blinded, block-randomized fashion.

Large animal models have good translational values in the examination of physiology and pharmacology of neonatal asphyxia. Using newborn piglets, we develop an experimental protocol to simulate neonatal asphyxia which has advantages of studying the systemic and regional hemodynamics, oxygen transport with biochemical and pathologic pathways and correlations.

Annually more than 1 million neonates die worldwide as related to asphyxia. Asphyxiated neonates commonly have multi-organ failure including hypotension, ...

Lavage-induced Surfactant Depletion in Pigs As a Model of the Acute Respiratory Distress Syndrome (ARDS)

Various animal models of lung injury exist to study the complex pathomechanisms of human acute respiratory distress syndrome (ARDS) and evaluate future therapies. Severe lung injury with a reproducible deterioration of pulmonary gas exchange and hemodynamics can be induced in anesthetized pigs using repeated lung lavages with warmed 0.9% saline (50 ml/kg body weight). Including standard respiratory and hemodynamic monitoring with clinically applied devices in this model allows the evaluation of novel therapeutic strategies (drugs, modern ventilators, extracorporeal membrane oxygenators, ECMO), and bridges the gap between bench and bedside. Furthermore, induction of lung injury with lung lavages does not require the injection of pathogens/endotoxins that impact on measurements of pro- and anti-inflammatory cytokines. A disadvantage of the model is the high recruitability of atelectatic lung tissue. Standardization of the model helps to avoid pitfalls, to ensure comparability between experiments, and to reduce the number of animals needed.

Lavage-induced Surfactant Depletion in Pigs As a Model of the Acute Respiratory Distress Syndrome ARDS

Repeated pulmonary lavages in anesthetized pigs induce lung injury resembling major aspects of human acute respiratory distress syndrome (ARDS). For this purpose the lungs are repeatedly lavaged with 0.9% saline at 37 &#176;C. The goal of the protocol is a reproducible mitigation of gas exchange and hemodynamics for research in ARDS.

Various animal models of lung injury exist to study the complex pathomechanisms of human acute respiratory distress syndrome (ARDS) and evaluate future ...

Surgical Placement of Catheters for Long-term Cardiovascular Exercise Testing in Swine

This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early cardiopulmonary dysfunction is difficult to diagnose, particularly in animal models, as cardiopulmonary function is often measured invasively, requiring anesthesia. As many anesthetic agents are cardiodepressive, subtle changes in cardiovascular function may be masked. In contrast, chronic instrumentation allows for measurement of cardiopulmonary function in the awake state, so that measurements can be obtained under quiet resting conditions, without the effects of anesthesia and acute surgical trauma. Furthermore, when animals are properly trained, measurements can also be obtained during graded treadmill exercise.
Flow probes are placed around the aorta or pulmonary artery for measurement of cardiac output and around the left anterior descending coronary artery for measurement of coronary blood flow. Fluid-filled catheters are implanted in the aorta, pulmonary artery, left atrium, left ventricle and right ventricle for pressure measurement and blood sampling. In addition, a 20 G&#160;catheter is positioned in the anterior interventricular vein to allow coronary venous blood sampling.
After a week of recovery, swine are placed on a motor-driven treadmill, the catheters are connected to pressure and flow meters, and swine are subjected to a five-stage progressive exercise protocol, with each stage lasting 3 min. Hemodynamic signals are continuously recorded and blood samples are taken during the last 30 sec of each exercise stage.
The major advantage of studying chronically instrumented animals is that it allows serial assessment of cardiopulmonary function, not only at rest but also during physical stress such as exercise. Moreover, cardiopulmonary function can be assessed repeatedly during disease development and during chronic treatment, thereby increasing statistical power and hence limiting the number of animals required for a study.

Here we present a protocol to assess cardiopulmonary function in awake swine, at rest and during graded treadmill exercise. Chronic instrumentation allows for repeated hemodynamic measurements uninfluenced by cardiodepressive anesthetic agents.

This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early ...

Direct Cannula Implantation in the Cisterna Magna of Pigs

The glymphatic system is a waste clearance system in the brain that relies on the flow of cerebrospinal fluid (CSF) in astrocyte-bound perivascular spaces and has been implicated in the clearance of neurotoxic peptides such as amyloid-beta. Impaired glymphatic function exacerbates disease pathology in animal models of neurodegenerative diseases, such as Alzheimer's, which highlights the importance of understanding this clearance system. The glymphatic system is often studied by cisterna magna cannulations (CMc), where tracers are delivered directly into the cerebrospinal fluid (CSF). Most studies, however, have been carried out in rodents. Here, we demonstrate an adaptation of the CMc technique in pigs. Using CMc in pigs, the glymphatic system can be studied at a high optical resolution in gyrencephalic brains and in doing so bridges the knowledge gap between rodent and human glymphatics.

This article presents a step-by-step protocol for the direct cannula implantation in the cisterna magna of pigs.

The glymphatic system is a waste clearance system in the brain that relies on the flow of cerebrospinal fluid (CSF) in astrocyte-bound perivascular spaces ...

Neuroscience

Microscopic Observation of Lymphocyte Dynamics in Rat Peyer's Patches

Na&#239;ve lymphocytes recirculate from the blood to the lymphoid tissues under physiological condition and it is commonly recognized as an important phenomenon in the gut immunity. The stroma of secondary lymphoid organs, such as Peyer&#8217;s patches (PPs) or mesenteric lymph nodes, are where na&#239;ve lymphocytes sense antigens. Na&#239;ve lymphocytes circulate through the bloodstream to reach high endothelial venules, the portal of entry into PPs. Some immunomodulators are estimated to influence lymphocyte migration, but the precise evaluation of microcirculation dynamics is very difficult, and establishing a method to observe lymphocyte migration in vivo can contribute to the clarification of the precise mechanisms. We refined the method of collecting lymphocytes from the lymph duct and observing the detailed dynamics of gut-tropic lymphocytes in rat PPs. We chose confocal laser scanning microscopy to observe rat PPs in vivo and recorded it using time-lapse photography. We can now obtain clear images that can contribute to the analysis of lymphocyte dynamics.

Here, we describe a precise method for collecting thoracic duct lymphocytes and observing the migration of gut-tropic lymphocytes in rat Peyer&#8217;s patches for 3 hours using time-lapse photography. This technique can clarify how the dynamics of lymphocytes are affected under inflammatory conditions.

Na&#239;ve lymphocytes recirculate from the blood to the lymphoid tissues under physiological condition and it is commonly recognized as an important ...

Intubation, Central Venous Catheter, and Arterial Line Placement in Swine for Translational Research in Abdominal Transplantation Surgery

Translational surgical research models in swine are crucial for developing safe preclinical protocols. However, the success of the experimental surgeries does not solely rely on the research team's surgical skills; perioperative care and management procedures, like intubation, central venous line, and arterial line placement, are necessary and of the utmost importance for favorable experiment results. As it is uncommon for research teams to have anesthesiologists or any other staff other than the surgical team, the surgical team involved in translational research must acquire and/or develop the skills to perform the perioperative care. The purpose of this paper is to show the techniques of intubation, central venous catheter, and arterial line placement used and perfected at the Toronto Organ Preservation Laboratory over the last 10 years, to be used as a reference for future researchers joining either this team or any other lab performing translational research protocols in swine and/or abdominal transplantation.

To obtain the best possible results, surgeons performing translational research experiments should be proficient at intubation and vascular line placement. This paper describes the techniques used by the Toronto Organ Preservation Laboratory to perform these procedures.

Translational surgical research models in swine are crucial for developing safe preclinical protocols. However, the success of the experimental surgeries ...

Hickman Catheter for Long-Term Vascular Access in Swine

Hickman Catheter Use for Long-Term Vascular Access in a Preclinical Swine Model

Central venous catheters (CVCs) are invaluable devices in large animal research as they facilitate a wide range of medical applications, including blood monitoring and reliable intravenous fluid and drug administration. Specifically, the tunneled multi-lumen Hickman catheter (HC) is commonly used in swine models due to its lower extrication and complication rates. Despite fewer complications relative to other CVCs, HC-related morbidity presents a significant challenge, as it can significantly delay or otherwise negatively impact ongoing studies. The proper insertion and maintenance of HCs is paramount in preventing these complications, but there is no consensus on best practices. The purpose of this protocol is to comprehensively describe an approach for the insertion and maintenance of a tunneled HC in swine that mitigates HC-related complications and morbidity. The use of these techniques in &gt;100 swine has resulted in complication-free patent lines up to 8 months and no catheter-related mortality or infection of the ventral surgical site. This protocol offers a method to optimize the lifespan of the HC and guidance for approaching issues during use.

Author Spotlight: Hickman Catheter Use for Long-Term Vascular Access in a Preclinical Swine Model  

A reliable and reproducible approach for the insertion and maintenance of a tunneled Hickman catheter for long-term vascular access in swine is described. Placement of a central venous catheter allows for convenient daily sampling of whole blood from awake animals and intravenous administration of medication and fluids.

Central venous catheters (CVCs) are invaluable devices in large animal research as they facilitate a wide range of medical applications, including blood ...

Surgical Technique for Lumbar Spinal Catheter Insertion in Pigs Enabling Continuous Access to the Thecal Sac in a Terminal Setup

Pigs are increasingly used as a large animal model for pharmacologic CNS research due to the anatomical and physiological similarities between the porcine and human central nervous systems (CNS). However, accessing the cerebrospinal fluid (CSF) in larger pig breeds by conventional lumbar puncture techniques can be challenging due to an oblique orientation of the spinal spinous processes and a limited interlaminar space. Accordingly, an open surgical procedure for inserting a lumbar spinal catheter for continuous CSF sampling at the L4/L5 level in pigs is thoroughly described in this work. After positioning the pig and identifying the anatomical landmarks, a dorsal midline surgical incision is made to expose the spinous processes. By advancing the introducer needle, the spinal catheter is inserted inside the thecal sac of the spinal canal while leaving the bone structures of the spine intact. This method allows continuous infusion into or sampling from the porcine thecal sac with minimal bleeding or CSF leakage. The procedure is simple, time-efficient, and reproducible across different experimental setups, offering significant potential for various pre-clinical studies, including pharmacokinetic research, surgical training, and spinal cord injury models.

We present a technique for inserting a lumbar spinal catheter at the L4-L5 level in a 3-month-old Danish Landrace pig as part of a terminal research protocol, enabling continuous infusion or CSF sampling from the thecal sac.

Pigs are increasingly used as a large animal model for pharmacologic CNS research due to the anatomical and physiological similarities between the porcine ...

Mesenteric Lymph Duct Cannulation in a Rat Model to Harvest Lymph Fluid

Source: Trevaskis, N. L., et al. <a href="https://appjove.unicartagenaproxy.elogim.com/v/52389">The Mesenteric Lymph Duct Cannulated Rat Model: Application to the Assessment of Intestinal Lymphatic Drug Transport.</a> J. Vis. Exp. (2015).
This video demonstrates a technique to cannulate the mesenteric lymph duct in rats. This method enables direct access to the entire volume of components present in the lymph fluid.

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
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