Name: a large animal model for acute kidney injury by temporary bilateral renal artery occlusion
Uploaded: 2021-02-02T15:00:00
Description: Watch this Scientific Journal Video about A Large Animal Model for Acute Kidney Injury by Temporary Bilateral Renal Artery Occlusion at JoVE.com

We would like to thank Dr. Arthur Nedder for his help and guidance. This work was supported by the Richard A. and Susan F. Smith President&#39;s Innovation Award, Michael B. Klein and Family, The Sidman Family Foundation, The Michael B. Rukin Charitable Foundation, The Kenneth C. Griffin Charitable Research Fund, and The Boston Investment Council.

All in vivo studies were conducted in accordance with the National Institutes of Health&#39;s guidelines on animal care and use and were approved by the Boston Children&#39;s Hospital&#39;s Animal Care and Use Committee (Protocol 18-06-3715). All animals received humane care in compliance with the Guide for the Care and Use of Laboratory Animals. Figure 1 shows the timeline including anesthesia, surgical preparation, and timepoints for primary outcome measurements of this study.
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A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Catheter-based+induction+of+renal+ischemia/reperfusion+in+swine:+Description+of+an+experimental+model.">Catheter-based induction of renal ischemia/reperfusion in swine: Description of an experimental model.</a> Physiological Reports. 2 (9), 1-13 (2014).</li><li>Freeman, R. 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AKI is a common clinical disorder affecting up to 50% of hospitalized adult patients worldwide6,12. A clinically relevant animal model is needed to further investigate the pathophysiology of the disease and potential therapeutic targets. Although there are several murine models replicating AKI, these do not completely mimic their respective clinical scenarios and the anatomy of the human kidney. This study proposes a clinically relevant swine model to allow for t...

Acute kidney injury (AKI) is a commonly diagnosed condition among surgical patients associated with significant morbidity and mortality1,2. Available data show that AKI can affect even half of all hospitalized patients worldwide and leads to 50% mortality rate in patients in the intensive care unit1,3. Despite its high prevalence, current AKI therapy remains limited to preventive strategies, such as fluid management and dialysis. Therefore, there is an ongoing interest in exploring alternative therapies for AKI4,5,6.
AKI is typically classified into pre-renal, intrinsic, and post-renal based on its etiology4,5,6. The majority of surgical patients with AKI are associated with pre-renal causes due to hypovolemia, resulting in ischemia-reperfusion injury (IRI) of the kidneys2. Clinically, urine output decreases, and creatinine levels increase due to decreased renal function. The kidney is a high-metabolic-rate organ and susceptible to ischemia. A highly reproducible large animal model of renal IRI is necessary to obtain a better insight into the pathophysiology of AKI and its potential therapeutic approaches5.
To mimic the clinical scenario of kidney hypoperfusion peri-operatively, a model of bilateral renal artery occlusion is deemed suitable. Previously described models entailing unilateral renal artery occlusion with or without resection of the contralateral kidney do not provide sufficient clinical applicability7,8. Although these models are sufficient for causing AKI, they do not resemble real-life clinical scenarios neither in terms of type nor duration of injury.
The aim of this paper is to present a porcine model of percutaneous bilateral temporary occlusion of the renal arteries by balloon-catheter occlusion under angiography. Bilateral renal artery occlusion mimics the clinical scenario of renal hypoperfusion, followed by the subsequent removal of the balloon for reperfusion9,10. The technical steps are described, including catheterization, catheter guidance, angiography, and hemodynamic monitoring. This method not only allows for a highly controlled and replicable occlusion of the renal arteries, but the percutaneous approach minimizes the impact of the inflammatory response by limiting the amount of insult to the body compared to an open approach.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.9% sodium chloride injection, usp, 100 ml viaflex plastic container</td>
			<td>Baxter</td>
			<td>2B1302</td>
			<td>For animal hydration</td>
		</tr>
		<tr>
			<td>Agent contrast 100.0ml injection media btl ioversal 74%</td>
			<td>CARDINAL HEALTH</td>
			<td>133311</td>
			<td>For visualizing the vasculature</td>
		</tr>
		<tr>
			<td>Bard Bardia Closed System Urinary Drainage Bag</td>
			<td>BARD Inc</td>
			<td>802001</td>
			<td>For urine collection</td>
		</tr>
		<tr>
			<td>BD Vacutainer K2 EDTA</td>
			<td>BD</td>
			<td>367841</td>
			<td>For blood sample storage</td>
		</tr>
		<tr>
			<td>BD Vacutainer Lithium Heparin</td>
			<td>BD</td>
			<td>366667</td>
			<td>For blood sample storage</td>
		</tr>
		<tr>
			<td>Betadine</td>
			<td>Henry Schein</td>
			<td>6906950</td>
			<td>For skin disinfection</td>
		</tr>
		<tr>
			<td>Bookwalker retractor</td>
			<td>Codman</td>
			<td></td>
			<td>For skin retraction</td>
		</tr>
		<tr>
			<td>Bupivacaine 0.25%</td>
			<td>Hospira</td>
			<td></td>
			<td>Administer at incision site for analgesia</td>
		</tr>
		<tr>
			<td>Buprenorphine SR</td>
			<td>Zoo Pharm</td>
			<td></td>
			<td>10mg/ml bottle, Dose: 0.2mg/kg SC</td>
		</tr>
		<tr>
			<td>Cath angio 5.0 Fr x100.0 cm 0.038 in JR4</td>
			<td>MERIT MEDICAL SYSTEM INC</td>
			<td>7523-21</td>
			<td>For identification of the renal arteries</td>
		</tr>
		<tr>
			<td>Cuffed endotracheal tube</td>
			<td>Emdamed</td>
			<td></td>
			<td>To establish a secure airway for the duration of the operation</td>
		</tr>
		<tr>
			<td>EKG Medtronics- Physiocontrol LifePak 20 Oxygen saturation monitor</td>
			<td>GE Healthcare Madison WI</td>
			<td></td>
			<td>For oxygen saturation monitoring</td>
		</tr>
		<tr>
			<td>Encore 26 inflator</td>
			<td>BOSTON SCIENTIFIC</td>
			<td>710113</td>
			<td>For inflating the balloon catheters</td>
		</tr>
		<tr>
			<td>Ethanol 95% (Ethyl alcohol)</td>
			<td>Henry Schein</td>
			<td></td>
			<td>For skin disinfection</td>
		</tr>
		<tr>
			<td>Fentanyl patch</td>
			<td>Mylan</td>
			<td></td>
			<td>Dose: 25-50mcg/hr, TD</td>
		</tr>
		<tr>
			<td>Gold silicone coated Foley</td>
			<td>TELEFLEX MEDICAL INC</td>
			<td>180730160</td>
			<td>For urine collection</td>
		</tr>
		<tr>
			<td>Heparin sodium</td>
			<td>LEO Pharma A/S</td>
			<td></td>
			<td>Dose: 200 IU/kg IV</td>
		</tr>
		<tr>
			<td>i33 ultrasound machine</td>
			<td>Phillips</td>
			<td></td>
			<td>Use ultrasonographic guidance for femoral catherization if necessary</td>
		</tr>
		<tr>
			<td>Inqwire diagnostic guide wire - 0.035&#34; (0.89 mm) - 260 cm (102&#34;) - 1.5 mm j-tip</td>
			<td>MERIT MEDICAL SYSTEM INC</td>
			<td>6609-33</td>
			<td>For guiding the balloon catheters to the renal arteries</td>
		</tr>
		<tr>
			<td>Intravenous catheter, size 20 gauge</td>
			<td>Santa Cruz Biotechnology</td>
			<td>Inc SC-360097</td>
			<td>For fluid administration</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Patterson Veterinary Supply, Inc.</td>
			<td>21283620</td>
			<td>Dose: 3%, INH</td>
		</tr>
		<tr>
			<td>Metzenbaum blunt curved 14.5 cm - 5(3/4)&#34;</td>
			<td>Rudolf Medical</td>
			<td>RU-1311-14M</td>
			<td>For tissue dissection and cutting</td>
		</tr>
		<tr>
			<td>Neonatal disposable transducer kit with 30ml/hr flush device and double 4-way stopcocks for continuous monitoring</td>
			<td>Argon Medical</td>
			<td>041588505A</td>
			<td>For pressure measurement</td>
		</tr>
		<tr>
			<td>Powerflex pro PTA dilatation catheter 6 x 20 mm - shaft length (135cm)</td>
			<td>CARDINAL HEALTH</td>
			<td>4400602X</td>
			<td>For occlusion of the renal arteries</td>
		</tr>
		<tr>
			<td>Pressure monitoring lines mll/mll - 12&#34; clear, mll/mll</td>
			<td>Smiths Medical</td>
			<td>B1571/MX571</td>
			<td>For pressure measurement</td>
		</tr>
		<tr>
			<td>Procedure pack</td>
			<td>Molnlycke Health Care</td>
			<td>97027809</td>
			<td>Surgical drape, gauze pads, syringes, beaker etc</td>
		</tr>
		<tr>
			<td>Protamine</td>
			<td>Henry Schein</td>
			<td>1044148</td>
			<td>For heparin reversal</td>
		</tr>
		<tr>
			<td>Scalpel blade - size #10</td>
			<td>Cardinal Health (Allegiance)</td>
			<td>32295-010</td>
			<td>For the skin incisions</td>
		</tr>
		<tr>
			<td>Stopcock iv 4 way lrg bore rotg male ll adptr strl</td>
			<td>Peoplesoft</td>
			<td>1550</td>
			<td>For connecting tubings</td>
		</tr>
		<tr>
			<td>Straight lateral retractor</td>
			<td>Codman</td>
			<td></td>
			<td>For skin retraction</td>
		</tr>
		<tr>
			<td>Suture perma hnd 18in 2-0 braid silk blk</td>
			<td>CARDINAL HEALTH 1</td>
			<td>A185H</td>
			<td>For suturing incision site and securing catheters</td>
		</tr>
		<tr>
			<td>Syringe contrast injection 10ml fixed male luer red</td>
			<td>MERIT MEDICAL SYSTEM INC</td>
			<td>MSS111-R</td>
			<td>To administer the contrast agent</td>
		</tr>
		<tr>
			<td>Syringe medical 60ml ll plst strl ltx free disp</td>
			<td>CARDINAL HEALTH 1</td>
			<td>BF309653</td>
			<td>For urine collection and flushing of the angiocath</td>
		</tr>
		<tr>
			<td>Tilzolan (tiletamine/zolazepam)</td>
			<td>Patterson Veterinary Supply, Inc.</td>
			<td>07-893-1467</td>
			<td>Dose: 4-6 mg/kg, IM</td>
		</tr>
		<tr>
			<td>Xylazine</td>
			<td>Putney, INC</td>
			<td></td>
			<td>Dose: 1.1-2.2 mg/kg, IM</td>
		</tr>
	</tbody>
</table>

a large animal model for acute kidney injury by temporary bilateral renal artery occlusion

Acute kidney injury (AKI) is associated with higher risk for morbidity and mortality post-operatively. Ischemia-reperfusion injury (IRI) is the most common cause of AKI. To mimic this clinical scenario, this study presents a highly reproducible large animal model of renal IRI in swine using temporary percutaneous bilateral balloon-catheter occlusion of the renal arteries. The renal arteries are occluded for 60 min by introducing the balloon-catheters through the femoral and carotid artery and advancing them into the proximal portion of the arteries. Iodinated contrast is injected in the aorta to assess any opacification of the kidney vessels and confirm the success of the artery occlusion. This is furtherly confirmed by the flattening of the pulse waveform at the tip of the balloon catheters. The balloons are deflated and removed after 60 min of bilateral renal artery occlusion, and the animals are allowed to recover for 24 h. At the end of the study, plasma creatinine and blood urea nitrogen significantly increase, while eGFR and urine output significantly decrease. The need for iodinated contrast is minimal and does not affect renal function. Bilateral renal artery occlusion better mimics the clinical scenario of perioperative renal hypoperfusion, and the percutaneous approach minimizes the impact of the inflammatory response and the risk of infection seen with an open approach, such as a laparotomy. The ability to create and reproduce this clinically relevant swine model eases the clinical translation to humans.

Functional analysis 
The representative results of this study arise from 6 animals and the data shown are mean &#177; standard error of the mean.Renal function is assessed by determining the urine output, estimated glomerular filtration rate (eGFR), plasma creatine, and blood urea nitrogen (BUN). The biomarkers of renal function are assessed using a portable chemistry analyzer. eGFR is calculated according to the following formula: eGFR =1.879 &#215; BW1.092/PCr0.6 (...

Watch this Scientific Journal Video about A Large Animal Model for Acute Kidney Injury by Temporary Bilateral Renal Artery Occlusion at JoVE.com

A Large Animal Model for Acute Kidney Injury by Temporary Bilateral Renal Artery Occlusion

This study presents a highly reproducible large animal model of renal ischemia-reperfusion injury in swine using temporary percutaneous bilateral balloon-catheter occlusion of the renal arteries for 60 min and reperfusion for 24 h.

Acute kidney injury (AKI) is associated with higher risk for morbidity and mortality post-operatively. Ischemia-reperfusion injury (IRI) is the most ...

This study describes a reproducible large animal model of renal ischemia reperfusion injury, which can be used to study the pathophysiology of acute kidney injury, and explore potential therapeutic modalities. This method is highly reproducible and minimizes the impact of inflammatory response by limiting the amount of insult to the body compared to an open approach. This preclinical model mimics clinical scenarios, such as renal transplantation, renal hypoperfusion following cardiogenic shock, transcatheter procedures resulting in renal ischemia, and cardiovascular procedures with prolonged cardio-circulatory arrest times.To begin, disinfect the right lateral area of the neck by applying betadine and then 95%ethanol three times. Drape the animal in a sterile fashion. Perform a cutdown for the catheterization of the right carotid artery and the right jugular vein.Retract the sternocleidomastoid muscle laterally, and dissect it down to the right carotid artery and the right jugular vein. Insert a 5F angiography sheath in both the artery and the vein. Secure it with a silk 2-0 suture.Insert a 5F angiography sheath using the Seldinger technique into the left femoral artery by puncturing the artery with a hollow needle. Insert a soft-tip guide wire through the lumen and advance it into the femoral artery. Hold the guide wire secure with a hand while removing the needle.Pass the angiography sheath over the guide wire into the femoral artery and withdraw the guide wire by using ultrasound guidance if necessary. Intravenously administer 200 IU per kilogram sodium heparin to achieve systemic anticoagulation. To perform angiography, inject an iodinated contrast agent under fluoroscopy to identify the renal arteries.Identify the renal arteries and manually advance the guide wire in the guiding catheter. Position the 5F JL4 guiding catheter in the left renal artery through the right carotid artery. Position the second 5F JL4 guiding catheter in the right renal artery through the left femoral artery.Use the guide wires to direct a 5F percutaneous transluminal angioplasty, or PTA dilation catheter, in each renal artery. Position each balloon catheter in place, and connect a pressure line to each catheter. Check the presence of arterial pulse wave forms in the pressure monitor to ensure the correct positioning of the catheter.Inflate each balloon and aim for a pressure of approximately 2.5 atmospheric pressure inside the balloon. To confirm the cessation of blood flow to the kidneys, observe the flattening of the pulse waveform at the tip of the balloon catheter. Inject iodinated contrast medium in a 1:1 dilution with saline and check for any opacification of the renal vessels.After 60 minutes of occlusion, carefully deflate and remove the balloon catheters from the renal arteries. Perform an angiography using a 1:1 diluted contrast medium to confirm renal artery patency and the establishment of renal reperfusion. Remove the 5F angiography sheath from the left femoral artery.Apply from pressure at the site of catheterization for 30 minutes. Reverse the effect of heparin by the administration of three milligrams per kilogram of protamine until normalization of active clotting time. To sample urine during the post-operative period, secure a tube to the Foley catheter with a silk 2-0 suture using an interrupted stitch on the skin.For blood sampling, leave the angiography sheaths in the right carotid artery and the right jugular vein in place, and secure them with a silk 2-0 suture. administer three milligrams per kilogram of bupivacaine at the incision site to minimize pain. Continue to hydrate the animal with 0.9 sodium chloride for a total of two hours following the end of ischemia.Close the neck incision with a silk 2-0 suture using an interrupted stitch in two layers. Place a fentanyl patch of 25 to 50 micrograms per hour on the back of the animal to minimize post-operative pain, and monitor the animal on mechanical ventilation until it awakens. Collect the final blood and urine samples and calculate the urine output.Perform a midline laparotomy incision using a size-10 blade from the xiphoid down to the mid pelvis. Use a straight lateral retractor to retract the abdominal skin. Dissect the lateral peritoneal attachments of the abdominal wall to expose the right and left retroperitoneum.Identify and bluntly dissect both renal arteries and veins. Ligate both renal arteries and veins with a 2-0 silk suture and perform bilateral nephrectomies to collect whole-tissue specimens for histological and metabolic analysis. Renal function was assessed by determining the urine output, eGFR, plasma creatine, and BUN.Following 60 minutes of bilateral renal artery occlusion, urine output was significantly decreased and remained this way at six and 24 hours following reperfusion. Similarly, a significant decrease was observed in eGFR, which dropped from baseline as compared to the end of ischemia at two hours, six hours, and 24 hours of reperfusion. Plasma creatinine was significantly increased at two, six, and 24 hours of reperfusion compared to baseline.BUN was increased as compared to baseline at six and 24 hours of reperfusion. Evident necrotic and hemorrhagic areas were unevenly distributed in both kidneys at the end of the 60 minutes of bilateral renal ischemia and the 24 hours of reperfusion. Masson's trichrome staining revealed confluent coagulative necrosis, which was located at the proximal tubules of the renal cortex.Plastic-embedded sections were also assessed. All Masson's trichrome slides were evaluated for cell necrosis, loss of brush border, cast formation, and tubule dilation. Acute tubular necrosis, or ATN scoring, showed significant injury to the renal cortex and medulla.When performing this protocol, check the positioning of the balloon sites on the proximity of RC, and totally occlude the flow to the kidney. Make sure it's not kinking in that water. Following this procedure, endovascular catheter flow probes can be inserted in the renal arteries to assess renal blood flow, or renal biopsies can be performed to assess renal tissue injury.

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Research

JoVE Journal

Medicine

Use of a Hanging-weight System for Isolated Renal Artery Occlusion

In hospitalized patients, over 50% of cases of acute kidney injury (AKI) are caused by renal ischemia 1-3. A recent study of hospitalized patients revealed that only a mild increase in serum creatinine levels (0.3 to 0.4 mg/dl) is associated with a 70% greater risk of death than in persons without any increase 1. Along these lines, surgical procedures requiring cross-clamping of the aorta and renal vessels are associated with a renal failure rates of up to 30% 4. Similarly, AKI after cardiac surgery occurs in over 10% of patients under normal circumstances and is associated with dramatic increases in mortality. AKI are also common complications after liver transplantation. At least 8-17% of patients end up requiring renal replacement therapy 5. Moreover, delayed graft function due to tubule cell injury during kidney transplantation is frequently related to ischemia-associated AKI 6. Moreover, AKI occurs in approximately 20% of patients suffering from sepsis 6.The occurrence of AKI is associated with dramatic increases of morbidity and mortality 1. Therapeutic approaches are very limited and the majority of interventional trials in AKI have failed in humans. Therefore, additional therapeutic modalities to prevent renal injury from ischemia are urgently needed 3, 7-9. 
To elucidate mechanisms of renal injury due to ischemia and possible therapeutic strategies murine models are intensively required 7-13. Mouse models provide the possibility of utilizing different genetic models including gene-targeted mice and tissue specific gene-targeted mice (cre-flox system). However, murine renal ischemia is technically challenging and experimental details significantly influence results. We performed a systematic evaluation of a novel model for isolated renal artery occlusion in mice, which specifically avoids the use of clamping or suturing the renal pedicle 14. This model requires a nephrectomy of the right kidney since ischemia can be only performed in one kidney due to the experimental setting. In fact, by using a hanging-weight system, the renal artery is only instrumented once throughout the surgical procedure. In addition, no venous or urethral obstruction occurs with this technique. We could demonstrate time-dose-dependent and highly reproducible renal injury with ischemia by measuring serum creatinine. Moreover, when comparing this new model with conventional clamping of the whole pedicle, renal protection by ischemic preconditioning is more profound and more reliable. Therefore his new technique might be useful for other researchers who are working in the field of acute kidney injury.

A precise murine model for acute kidney injury (AKI) due to ischemia is an important tool to investigate acute kidney injury and possibly find therapeutic tools to treat renal injury. The hanging weight system offers a tool for immediate and reliable renal artery occlusion and reperfusion without causing renal congestion.

In hospitalized patients, over 50% of cases of acute kidney injury (AKI) are caused by renal ischemia 1-3. A recent study of hospitalized patients ...

Ischemia-reperfusion Model of Acute Kidney Injury and Post Injury Fibrosis in Mice

Ischemia-reperfusion induced acute kidney injury (IR-AKI) is widely used as a model of AKI in mice, but results are often quite variable with high, often unreported mortality rates that may confound analyses. Bilateral renal pedicle clamping is commonly used to induce IR-AKI, but differences between effective clamp pressures and/or renal responses to ischemia between kidneys often lead to more variable results. In addition, shorter clamp times are known to induce more variable tubular injury, and while mice undergoing bilateral injury with longer clamp times develop more consistent tubular injury, they often die within the first 3 days after injury due to severe renal insufficiency. To improve post-injury survival and obtain more consistent and predictable results, we have developed two models of unilateral ischemia-reperfusion injury followed by contralateral nephrectomy. Both surgeries are performed using a dorsal approach, reducing surgical stress resulting from ventral laparotomy, commonly used for mouse IR-AKI surgeries. For induction of moderate injury BALB/c mice undergo unilateral clamping of the renal pedicle for 26 min and also undergo simultaneous contralateral nephrectomy. Using this approach, 50-60% of mice develop moderate AKI 24 hr after injury but 90-100% of mice survive. To induce more severe AKI, BALB/c mice undergo renal pedicle clamping for 30 min followed by contralateral nephrectomy 8 days after injury. This allows functional assessment of renal recovery after injury with 90-100% survival. Early post-injury tubular damage as well as post injury fibrosis are highly consistent using this model.

We describe models of moderate and severe ischemia-reperfusion-induced kidney injury in which the mice undergo unilateral renal pedicle clamping followed by simultaneous or delayed contralateral nephrectomy, respectively. These models consistently give rise to renal dysfunction and post-injury fibrosis, but injury severity and survival are dependent on mouse background, age and surgical equipment.

Ischemia-reperfusion induced acute kidney injury (IR-AKI) is widely used as a model of AKI in mice, but results are often quite variable with high, often ...

Renal Ischaemia Reperfusion Injury: A Mouse Model of Injury and Regeneration

Renal ischaemia reperfusion injury (IRI) is a common cause of acute kidney injury (AKI) in patients and occlusion of renal blood flow is unavoidable during renal transplantation. Experimental models that accurately and reproducibly recapitulate renal IRI are crucial in dissecting the pathophysiology of AKI and the development of novel therapeutic agents. Presented here is a mouse model of renal IRI that results in reproducible AKI. This is achieved by a midline laparotomy approach for the surgery with one incision allowing both a right nephrectomy that provides control tissue and clamping of the left renal pedicle to induce ischaemia of the left kidney. By careful monitoring of the clamp position and body temperature during the period of ischaemia this model achieves reproducible functional and structural injury. Mice sacrificed 24 hr&#160;following surgery demonstrate loss of renal function with elevation of the serum or plasma creatinine level as well as structural kidney damage with acute tubular necrosis evident. Renal function improves and the acute tissue injury resolves during the course of 7 days following renal IRI such that this model may be used to study renal regeneration. This model of renal IRI has been utilized to study the molecular and cellular pathophysiology of AKI as well as analysis of the subsequent renal regeneration.

The mouse model of renal ischaemia reperfusion injury described here comprises of a right nephrectomy that provides control tissue and clamping of the left renal pedicle to induce ischaemia that results in acute kidney injury. This model uses a midline laparotomy approach with all steps performed via one incision.

Renal ischaemia reperfusion injury (IRI) is a common cause of acute kidney injury (AKI) in patients and occlusion of renal blood flow is unavoidable ...

Invasive Hemodynamic Monitoring of Aortic and Pulmonary Artery Hemodynamics in a Large Animal Model of ARDS

One of the leading causes of morbidity and mortality in patients with heart failure is right ventricular (RV) dysfunction, especially if it is due to pulmonary hypertension. For a better understanding and treatment of this disease, precise hemodynamic monitoring of left and right ventricular parameters is important. For this reason, it is essential to establish experimental pig models of cardiac hemodynamics and measurements for research purpose. 
This article shows the induction of ARDS by using oleic acid (OA) and consequent right ventricular dysfunction, as well as the instrumentation of the pigs and the data acquisition process that is needed to assess hemodynamic parameters. To achieve right ventricular dysfunction, we used oleic acid (OA) to cause ARDS and accompanied this with pulmonary artery hypertension (PAH). With this model of PAH and consecutive right ventricular dysfunction, many hemodynamic parameters can be measured, and right ventricular volume load can be detected. 
All vital parameters, including respiratory rate (RR), heart rate (HR) and body temperature were recorded throughout the whole experiment. Hemodynamic parameters including femoral artery pressure (FAP), aortic pressure (AP), right ventricular pressure (peak systolic, end systolic and end diastolic right ventricular pressure), central venous pressure (CVP), pulmonary artery pressure (PAP) and left arterial pressure (LAP) were measured as well as perfusion parameters including ascending aortic flow (AAF) and pulmonary artery flow (PAF). Hemodynamic measurements were performed using transcardiopulmonary thermodilution to provide cardiac output (CO). Furthermore, the PiCCO2 system (Pulse Contour Cardiac Output System 2) was used to receive parameters such as stroke volume variance (SVV), pulse pressure variance (PPV), as well as extravascular lung water (EVLW) and global end-diastolic volume (GEDV). Our monitoring procedure is suitable for detecting right ventricular dysfunction and monitoring hemodynamic findings before and after volume administration.

We present a protocol of creating right ventricular dysfunction in a pig model by inducing ARDS. We demonstrate invasive monitoring of left and right ventricular cardiac output using flow probes around the aorta and the pulmonary artery, as well as blood pressure measurements in the aorta and pulmonary artery.

One of the leading causes of morbidity and mortality in patients with heart failure is right ventricular (RV) dysfunction, especially if it is due to ...

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, ...

Induction and Phenotyping of Acute Right Heart Failure in a Large Animal Model of Chronic Thromboembolic Pulmonary Hypertension

The development of acute right heart failure (ARHF) in the context of chronic pulmonary hypertension (PH) is associated with poor short-term outcomes. The morphological and functional phenotyping of the right ventricle is of particular importance in the context of hemodynamic compromise in patients with ARHF. Here, we describe a method to induce ARHF in a previously described large animal model of chronic PH, and to phenotype, dynamically, right ventricular function using the gold standard method (i.e., pressure-volume PV loops) and with a non-invasive clinically available method (i.e., echocardiography). Chronic PH is first induced in pigs by left pulmonary artery ligation and right lower lobe embolism with biological glue once a week for 5 weeks. After 16 weeks, ARHF is induced by successive volume loading using saline followed by iterative pulmonary embolism until the ratio of the systolic pulmonary pressure over systemic pressure reaches 0.9 or until the systolic systemic pressure decreases below 90 mmHg. Hemodynamics are restored with dobutamine infusion (from 2.5 &#181;g/kg/min to 7.5 &#181;g/kg/min). PV-loops and echocardiography are performed during each condition. Each condition requires around 40 minutes for induction, hemodynamic stabilization and data acquisition. Out of 9 animals, 2 died immediately after pulmonary embolism and 7 completed the protocol, which illustrates the learning curve of the model. The model induced a 3-fold increase in mean pulmonary artery pressure. The PV-loop analysis showed that ventriculo-arterial coupling was preserved after volume loading, decreased after acute pulmonary embolism and was restored with dobutamine. Echocardiographic acquisitions allowed to quantify right ventricular parameters of morphology and function with good quality. We identified right ventricular ischemic lesions in the model. The model can be used to compare different treatments or to validate non-invasive parameters of right ventricular morphology and function in the context of ARHF.

We present a protocol to induce and phenotype an acute right heart failure in a large animal model with chronic pulmonary hypertension. This model can be used to test therapeutic interventions, to develop right heart metrics&#160;or to improve the understanding of acute right heart failure pathophysiology.

The development of acute right heart failure (ARHF) in the context of chronic pulmonary hypertension (PH) is associated with poor short-term outcomes. The ...

Isometric Contractility Measurement of the Mouse Mesenteric Artery Using Wire Myography

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and drugs. It is widely used in many studies on the physiological functions of vascular smooth muscle, the pathogenesis of vascular diseases such as hypertension, and the development of smooth muscle relaxant drugs. The mouse is a widely used model animal with a large pool of disease models and genetically modified strains. We introduced this method to measure the isometric contraction of mouse mesenteric artery in detail. A 1.4-mm segment of mouse mesenteric resistance artery was isolated and mounted on a myograph chamber by passing two steel wires through its lumen. After equilibration and normalization steps, the vessel segment was potentiated by a high-K+ solution twice prior to the contraction assay. As an example of the application of this method in drug development, we measured the relaxant effect of a novel natural substance, neoliensinine, isolated from a Chinese herb, embryos of the lotus seed (Nelumbo nucifera Gaertn.) on mouse mesenteric arteries. The vessel segments mounted on the myograph chamber were stimulated with a high-K+ solution. When the force tension reached a stable sustained phase, cumulative doses of neoliensinine were added to the chamber. We found that neoliensinine had a dose-dependent relaxant effect on smooth muscle contraction, thus suggesting that it bears potential activity against hypertension. In addition, as the vessel segment can survive at least 4 hours after mounting and maintain contractility induced by the high-K+ solution for many times, we suggest that the wire myograph system may be used for the time-consuming process of drug screening.

The wire myograph technique is used to investigate vascular smooth muscle functions and screen new drugs. We report a detailed protocol for measuring the isometric contractility of the mouse mesenteric artery and for screening new relaxants of vascular smooth muscle.

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and ...

A Modified Two Kidney One Clip Mouse Model of Renin Regulation in Renal Artery Stenosis

Renal artery stenosis is a common condition in patients with coronary or peripheral vascular disease where the renin angiotensin aldosterone system (RAAS) is overactivated. In this context, there is a narrowing of the renal arteries that stimulate an increase in the expression and release of renin, the rate-limiting protease in RAAS. The resulting rise in renin expression is a known driver of renovascular hypertension, frequently associated with kidney injury and end organ damage. Thus, there is a great interest in developing novel treatments for this condition. The molecular and cellular mechanism of renin control in renal artery stenosis is not fully understood and warrants further investigation. To induce renal artery stenosis in mice, a modified 2 kidney 1 clip (2K1C) Goldblatt mouse model was developed. The right kidney was stenosed in wild type mice and sham operated mice were used as control. After renal artery stenosis, we determined renin expression and kidney injury. Kidneys were harvested, and fresh cortices were used to determine protein and mRNA expression of renin. This animal model is reproducible and can be used to study pathophysiological responses, molecular and cellular pathways involved in renovascular hypertension and kidney injury.

A modified 2 kidney 1 clip (2K1C) Goldblatt mouse model was developed using polyurethane tubing to initiate renal artery stenosis, inducing an increase in renin expression and kidney injury. Here, we describe a detailed procedure of preparing and placing the cuff onto the renal artery to generate a reproducible and consistent 2K1C mouse model.

Renal artery stenosis is a common condition in patients with coronary or peripheral vascular disease where the renin angiotensin aldosterone system (RAAS) ...

Acute Kidney Injury Model Induced by Cisplatin in Adult Zebrafish

Cisplatin is commonly used as chemotherapy. Although it has positive effects in cancer-treated individuals, cisplatin can easily accumulate in the kidney due to its low molecular weight. Such accumulation causes the death of tubular cells and can induce the development of Acute Kidney Injury (AKI), which is characterized by a quick decrease in kidney function, tissue damage, and immune cells infiltration. If administered in specific doses cisplatin can be a useful tool as an AKI inducer in animal models. The zebrafish has appeared as an interesting model to study renal function, kidney regeneration, and injury, as renal structures conserve functional similarities with mammals. Adult zebrafish injected with cisplatin shows decreased survival, kidney cell death, and increased inflammation markers after 24 h post-injection (hpi). In this model, immune cells infiltration and cell death can be assessed by flow cytometry and TUNEL assay. This protocol describes the procedures to induce AKI in adult zebrafish by intraperitoneal cisplatin injection and subsequently demonstrates how to collect the renal tissue for flow cytometry processing and cell death TUNEL assay. These techniques will be useful to understand the effects of cisplatin as a nephrotoxic agent and will contribute to the expansion of AKI models in adult zebrafish. This model can also be used to study kidney regeneration, in the search for compounds that treat or prevent kidney damage and to study inflammation in AKI. Moreover, the methods used in this protocol will improve the characterization of tissue damage and inflammation, which are therapeutic targets in kidney-associated comorbidities.

This protocol describes the procedures to induce Acute Kidney Injury (AKI) in adult zebrafish using cisplatin as a nephrotoxic agent. We detailed the steps to evaluate the reproducibility of the technique and two techniques to analyze inflammation and cell death in the renal tissue, flow cytometry and TUNEL, respectively.

Cisplatin is commonly used as chemotherapy. Although it has positive effects in cancer-treated individuals, cisplatin can easily accumulate in the kidney ...

A Murine Model of Ischemic Retinal Injury Induced by Transient Bilateral Common Carotid Artery Occlusion

Diverse vascular diseases such as diabetic retinopathy, occlusion of retinal veins or arteries and ocular ischemic syndrome can lead to retinal ischemia. To investigate pathological mechanisms of retinal ischemia, relevant experimental models need to be developed. Anatomically, a main retinal blood supplying vessel is the ophthalmic artery (OpA) and OpA originates from the internal carotid artery of the common carotid artery (CCA). Thus, disruption of CCA could effectively cause retinal ischemia. Here, we established a mouse model of retinal ischemia by transient bilateral common carotid artery occlusion (tBCCAO) to tie the right CCA with 6-0 silk sutures and to occlude the left CCA transiently for 2 seconds via a clamp, and showed that tBCCAO could induce acute retinal ischemia leading to retinal dysfunction. The current method reduces reliance on surgical instruments by only using surgical needles and a clamp, shortens occlusion time to minimize unexpected animal death, which is often seen in mouse models of middle cerebral artery occlusion, and maintains reproducibility of common retinal ischemic findings. The model can be utilized to investigate the pathophysiology of ischemic retinopathies in mice and further can be used for in vivo drug screening.

Here, we describe a mouse model of retinal ischemia by transient bilateral common carotid artery occlusion using simple sutures and a clamp. This model can be useful for understanding the pathological mechanisms of retinal ischemia caused by cardiovascular abnormalities.

Diverse vascular diseases such as diabetic retinopathy, occlusion of retinal veins or arteries and ocular ischemic syndrome can lead to retinal ischemia. ...