This work was supported, in part, by a Joint Biology Consortium Microgrant provided under NIH grant P30AR070253 (PYC), Cardiovascular Medical Research Education Fund (PYC), VasoRx, Inc. Fund (MS) and NIH grants HL135582 (MS), HL152197 (MS).

<ol>
	<li>McLaughlin, V. V., McGoon, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulmonary+arterial+hypertension.">Pulmonary arterial hypertension.</a> Circulation. 114 (1), 1417-1431 (2006).</li><li>Hoeper, M. M., Humbert, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+new+haemodynamic+definition+of+pulmonary+hypertension:+evidence+prevails,+finally.">The new haemodynamic definition of pulmonary hypertension: evidence prevails, finally.</a> European Respiratory Journal. 53 (3), 1900038 (2019).</li><li>Chen, Y., 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=A+novel+rat+model+of+pulmonary+hypertension+induced+by+mono+treatment+with+SU5416.">A novel rat model of pulmonary hypertension induced by mono treatment with SU5416.</a> Hypertension Research. 43 (8), 754-764 (2020).</li><li>Xiong, M., 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=Mouse+model+of+experimental+pulmonary+hypertension:+Lung+angiogram+and+right+heart+catheterization.">Mouse model of experimental pulmonary hypertension: Lung angiogram and right heart catheterization.</a> Pulmonary Circulation. 11 (4), 20458940211041512 (2021).</li><li>Kmiotek, E. K., Baimel, C., Gill, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+for+intravenous+self+administration+in+a+mouse+model.">Methods for intravenous self administration in a mouse model.</a> Journal of Visualized Experiments. (70), e3739 (2012).</li><li>Potus, F., Martin, A. Y., Snetsinger, B., Archer, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biventricular+assessment+of+cardiac+function+and+pressure-volume+loops+by+closed-chest+catheterization+in+mice.">Biventricular assessment of cardiac function and pressure-volume loops by closed-chest catheterization in mice.</a> Journal of Visualized Experiments. (160), e61088 (2020).</li><li>Bueno-Beti, C., Hadri, L., Hajjar, R. J., Sassi, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Sugen+5416/hypoxia+mouse+model+of+pulmonary+arterial+hypertension.">The Sugen 5416/hypoxia mouse model of pulmonary arterial hypertension.</a> Experimental Models of Cardiovascular Diseases. 1816, 243-252 (2018).</li><li>Chen, P. Y., 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=FGF+regulates+TGF-beta+signaling+and+endothelial-to-mesenchymal+transition+via+control+of+let-7+miRNA+expression.">FGF regulates TGF-beta signaling and endothelial-to-mesenchymal transition via control of let-7 miRNA expression.</a> Cell Reports. 2 (6), 1684-1696 (2012).</li><li>Chen, P. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial+TGF-beta+signalling+drives+vascular+inflammation+and+atherosclerosis.">Endothelial TGF-beta signalling drives vascular inflammation and atherosclerosis.</a> Nature Metabolism. 1 (9), 912-926 (2019).</li><li>Daugherty, A., Rateri, D., Hong, L., Balakrishnan, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+blood+pressure+in+mice+using+volume+pressure+recording,+a+tail-cuff+method.">Measuring blood pressure in mice using volume pressure recording, a tail-cuff method.</a> Journal of Visualized Experiments. (27), e1291 (2009).</li><li>Alam, M. A., Parks, C., Mancarella, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+blood+pressure+measurement+in+freely+moving+mice+using+telemetry.">Long-term blood pressure measurement in freely moving mice using telemetry.</a> Journal of Visualized Experiments. (111), e53991 (2016).</li><li>Luo, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Invasive+hemodynamic+assessment+for+the+right+ventricular+system+and+hypoxia-induced+pulmonary+arterial+hypertension+in+mice.">Invasive hemodynamic assessment for the right ventricular system and hypoxia-induced pulmonary arterial hypertension in mice.</a> Journal of Visualized Experiments. (152), e60090 (2019).</li></ol>

K Zsebo, M Simons, and P-Y Chen are scientific founders and shareholders of VasoRx, Inc. M Simons is a member of the Scientific Advisory Board of VasoRx, Inc. HJ Duckers is an employee and shareholder of VasoRx. The other authors declare no competing interests.

Several pulmonary hypertension animal models have been established to mimic the elevated pulmonary vascular resistance events in human subjects. Among them, the mouse hypoxia-induced PAH model has been widely used for evaluating the effectiveness of new experimental therapies for PAH. Research using this model often requires the administration of compounds to the mice. In comparison with other published intravenous (IV) injection and invasive hemodynamic assessment protocols, this method provides both visual illustration...

Pulmonary artery hypertension (PAH) is defined by a mean pulmonary artery systolic pressure greater than 20 mmHg at rest1,2. It is a progressive and fatal disease characterized by a sustained elevation in pulmonary arterial pressure, leading to right ventricle overload and ultimately death due to right ventricular failure1. Currently, there is no cure for PAH.
The use of animal models of pulmonary hypertension is important for testing the effectiveness of experimental PAH therapies. Among those models, the mouse hypoxia-induced PAH model has provided key insights into human PAH group 3 disease development3,4. Research using this model often requires the administration of compounds in mice to evaluate the novel compound&#39;s effectiveness and safety. Therefore, investigators need a detailed experimental procedure for compound dosing and hemodynamic measurements to ensure injection consistency and blood pressure measurement reproducibility from the beginning to the end.
Methods for intravenous (IV)&#160;injection and blood pressure measuring have been reported in the literature5,6. However, the methodology lacks visual illustration and detailed description. Here we illustrate the key steps for a successful IV bolus injection and accurate measurement and recording of systemic and right ventricle blood pressure. The procedures presented here are an important resource for investigators interested in the IV route of compound administration platform to develop a treatment for PAH.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>5-0 prolene suture pack</td>
			<td>Ethicon</td>
			<td>8698G</td>
			<td>for incision closure</td>
		</tr>
		<tr>
			<td>8-0 nylon suture pack</td>
			<td>AROSurgical Instruments</td>
			<td>T06A08N14-13</td>
			<td>for ligation</td>
		</tr>
		<tr>
			<td>Anesthesia induction chamber</td>
			<td>VETEQUIP</td>
			<td>#941444</td>
			<td>Holds the animal during anesthesia exposure</td>
		</tr>
		<tr>
			<td>Catheter Interface Cable PEC-4D</td>
			<td>Millar</td>
			<td></td>
			<td>for connecting Millar Mikro-Tip catheter to PCU-2000</td>
		</tr>
		<tr>
			<td>Charcoal canister filters</td>
			<td>VETEQUIP</td>
			<td>#931401</td>
			<td>&#160;to help remove&#160;waste anesthetic&#160;gases</td>
		</tr>
		<tr>
			<td>Cotton swabs</td>
			<td>McKesson</td>
			<td>24-106</td>
			<td>for applying pressure to the injection site to prevent bleeding</td>
		</tr>
		<tr>
			<td>Fine scissors</td>
			<td>Fine Science Tools</td>
			<td>14059-11</td>
			<td>Surgical tools</td>
		</tr>
		<tr>
			<td>Insulin syringe 28 G</td>
			<td>EXEL</td>
			<td>26027</td>
			<td>for jugular vein IV injection</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>COVETRUS</td>
			<td>#029405</td>
			<td>for mouse anesthesia</td>
		</tr>
		<tr>
			<td>LabChart 8 Software</td>
			<td>ADInstruments</td>
			<td></td>
			<td>for data analysis</td>
		</tr>
		<tr>
			<td>Mikro-Tip Pressure Catheter SPR-1000 (1.0 F)</td>
			<td>Millar</td>
			<td></td>
			<td>for invasive blood pressure measurement</td>
		</tr>
		<tr>
			<td>Needle-25 G</td>
			<td>BD</td>
			<td>305124</td>
			<td>for making a samll hole in a vessel</td>
		</tr>
		<tr>
			<td>Oxygen controller ProOx Oxygen Sensor</td>
			<td>BioSpherix</td>
			<td>E702</td>
			<td>for oxygen concentration monitoring</td>
		</tr>
		<tr>
			<td>PCU-2000 Pressure Control Unit</td>
			<td>Millar</td>
			<td></td>
			<td>for connecting Millar Mikro-Tip catheter to PowerLab 4/35</td>
		</tr>
		<tr>
			<td>PowerLab 4/35</td>
			<td>ADInstruments</td>
			<td></td>
			<td>for Data Acquisition. 
			Investigator needs to connect the PowerLab 4/35 to a personal laptop containing LabChart 8 software for operation.</td>
		</tr>
		<tr>
			<td>Prism 8</td>
			<td>GraphPad</td>
			<td></td>
			<td>for statistics and scientific graphing</td>
		</tr>
		<tr>
			<td>Semisealable hypoxia chamber</td>
			<td>BioSpherix</td>
			<td></td>
			<td>an artificial environment that simulates high-altitude conditions for animals</td>
		</tr>
		<tr>
			<td>Spring Scissors</td>
			<td>Fine Science Tools</td>
			<td>15021-15</td>
			<td>Surgical tools</td>
		</tr>
		<tr>
			<td>Tweezer Style 4</td>
			<td>Electron Microscopy Sciences</td>
			<td>0302-4-PO</td>
			<td>Surgical tools</td>
		</tr>
		<tr>
			<td>VasoRx compound 7C1/let-7 miRNA</td>
			<td>VasoRx, Inc.</td>
			<td>Lot# B2-L-16Apr</td>
			<td>IV injection compound</td>
		</tr>
		<tr>
			<td>VIP 3000 Veterinary Vaporizer</td>
			<td>COLONIAL MEDICAL SUPPLY CO., INC.</td>
			<td></td>
			<td>for accurate anesthesia delivery</td>
		</tr>
	</tbody>
</table>

multiple intravenous bolus dosing and invasive hemodynamic assessment in a hypoxia-induced mouse pulmonary artery hypertension model

Pulmonary arterial hypertension (PAH) is a progressive life-threatening disease, primarily affecting small pulmonary arterioles of the lung. Currently, there is no cure for PAH. It is important to discover new compounds that can be used to treat PAH. The mouse hypoxia-induced PAH model is a widely used model for PAH research. This model recapitulates human clinical manifestations of PAH Group 3 disease and is an important research tool to evaluate the effectiveness of new experimental therapies for PAH. Research using this model often requires the administration of compounds in mice. For a compound that needs to be given directly into the bloodstream, optimizing intravenous (IV) administration is a key part of the experimental procedures. Ideally, the IV injection system should permit multiple injections over a set time course. Although the mouse hypoxia-induced PAH model is very popular in many laboratories, it is technically challenging to perform multiple IV bolus dosing and invasive hemodynamic assessment in this model. In this protocol, we present step-by-step instructions on how to carry out multiple IV bolus dosing via mouse jugular vein and perform arterial and right ventricle catheterization for hemodynamic assessment in mouse hypoxia-induced PAH model.

Anesthesia often reduces blood pressure. Therefore, a minimum dose of anesthesia was used to abolish the movements in response to a noxious stimulus. Successful right ventricular chamber access can be visualized as the hemodynamic waveform changes in different regions of venous systems (Figure 8).
In this study, mice were randomly assigned to the normoxic (21% O2) group (n = 10), hypoxia (10% O2) group (n = 10), or hypoxia + 7C1/let-7 treatme...

Watch this Scientific Journal Video about Multiple Intravenous Bolus Dosing and Invasive Hemodynamic Assessment in a Hypoxia-Induced Mouse Pulmonary Artery Hypertension Model at JoVE.com

Multiple Intravenous Bolus Dosing and Invasive Hemodynamic Assessment in a Hypoxia-Induced Mouse Pulmonary Artery Hypertension Model

This protocol provides a step-by-step procedure for executing multiple intravenous bolus dose administration and invasive hemodynamic monitoring in mice. Investigators can use this protocol for future therapeutic compound screening for pulmonary artery hypertension.

Pulmonary arterial hypertension (PAH) is a progressive life-threatening disease, primarily affecting small pulmonary arterioles of the lung. Currently, ...

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1.3K Views.  Yale University School of Medicine. This protocol provides a step-by-step procedure for executing multiple intravenous bolus dose administration and invasive hemodynamic monitoring in mice. Investigators can use this protocol for future therapeutic compound screening for pulmonary artery hypertension.

Video: Multiple Intravenous Bolus Dosing and Invasive Hemodynamic Assessment in a Hypoxia-Induced Mouse Pulmonary Artery Hypertension Model

Human Internal Mammary Artery (IMA) Transplantation and Stenting: A Human Model to Study the Development of In-Stent Restenosis

Preclinical in vivo research models to investigate pathobiological and pathophysiological processes in the development of intimal hyperplasia after vessel stenting are crucial for translational approaches1,2.
The commonly used animal models include mice, rats, rabbits, and pigs3-5. However, the translation of these models into clinical settings remains difficult, since those biological processes are already studied in animal vessels but never performed before in human research models6,7. In this video we demonstrate a new humanized model to overcome this translational gap. The shown procedure is reproducible, easy, and fast to perform and is suitable to study the development of intimal hyperplasia and the applicability of diverse stents.
This video shows how to perform the stent technique in human vessels followed by transplantation into immunodeficient rats, and identifies the origin of proliferating cells as human.

Human Internal Mammary Artery IMA Transplantation and Stenting: A Human Model to Study the Development of In-Stent Restenosis

This video shows a model to study the development of intimal hyperplasia after stent deployment using a human vessel (IMA) in an immunodeficient rat model.

Preclinical in vivo research models to investigate pathobiological and pathophysiological processes in the development of intimal hyperplasia after vessel ...

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

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

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

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

Assessment of Right Ventricular Structure and Function in Mouse Model of Pulmonary Artery Constriction by Transthoracic Echocardiography

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, the RV is significantly affected in pulmonary diseases such as pulmonary artery hypertension (PAH). In addition, the RV is remarkably sensitive to cardiac pathologies, including left ventricular (LV) dysfunction, valvular disease or RV infarction4. To understand the role of RV in the pathogenesis of cardiac diseases, a reliable and noninvasive method to access the RV structurally and functionally is essential.
A noninvasive trans-thoracic echocardiography (TTE) based methodology was established and validated for monitoring dynamic changes in RV structure and function in adult mice. To impose RV stress, we employed a surgical model of pulmonary artery constriction (PAC) and measured the RV response over a 7-day period using a high-frequency ultrasound microimaging system. Sham operated mice were used as controls. Images were acquired in lightly anesthetized mice at baseline (before surgery), day 0 (immediately post-surgery), day 3, and day 7 (post-surgery). Data was analyzed offline using software.
Several acoustic windows (B, M, and Color Doppler modes), which can be consistently obtained in mice, allowed for reliable and reproducible measurement of RV structure (including RV wall thickness, end-diastolic&#160;and end-systolic dimensions), and function (fractional area change, fractional shortening, PA peak velocity, and peak pressure gradient) in normal mice and following PAC.
Using this method, the pressure-gradient resulting from PAC was accurately measured in real-time using Color Doppler mode and was comparable to direct pressure measurements performed with a Millar high-fidelity microtip catheter. Taken together, these data demonstrate that RV measurements obtained from various complimentary views using echocardiography are reliable, reproducible and can provide insights regarding RV structure and function. This method will enable a better understanding of the role of RV cardiac dysfunction.

Right ventricle (RV) dysfunction is critical to the pathogenesis of cardiovascular disease, yet limited methodologies are available for its evaluation. Recent advances in ultrasound imaging provide a noninvasive and accurate option for longitudinal RV study. Herein, we detail a step-by-step echocardiographic method using a murine model of RV pressure overload.

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, ...

Increasing Pulmonary Artery Pulsatile Flow Improves Hypoxic Pulmonary Hypertension in Piglets

Pulmonary arterial hypertension (PAH) is a disease affecting distal pulmonary arteries (PA). These arteries are deformed, leading to right ventricular failure. Current treatments are limited. Physiologically, pulsatile blood flow is detrimental to the vasculature. In response to sustained pulsatile stress, vessels release nitric oxide (NO) to induce vasodilation for self-protection. Based on this observation, this study developed a protocol to assess whether an artificial pulmonary pulsatile blood flow could induce an NO-dependent decrease in pulmonary artery pressure. One group of piglets was exposed to chronic hypoxia for 3 weeks and compared to a control group of piglets. Once a week, the piglets underwent echocardiography to assess PAH severity. At the end of hypoxia exposure, the piglets were subjected to a pulsatile protocol using a pulsatile catheter. After being anesthetized and prepared for surgery, the jugular vein of the piglet was isolated and the catheter was introduced through the right atrium, the right ventricle and the pulmonary artery, under radioscopic control. Pulmonary artery pressure (PAP) was measured before (T0), immediately after (T1) and 30 min after (T2) the pulsatile protocol. It was demonstrated that this pulsatile protocol is a safe and efficient method of inducing a significant reduction in mean PAP via an NO-dependent mechanism. These data open up new avenues for the clinical management of PAH.

Pulmonary hypertension is associated with a significant reduction in pulmonary artery pulsatility, contractility and elasticity, contributing to an increase in pulmonary artery pressure and pulmonary resistance. Using a hypoxic piglet model, this study demonstrated that improving pulmonary artery plasticity using a newly developed pulsatile catheter improves hypoxic pulmonary hypertension.

Pulmonary arterial hypertension (PAH) is a disease affecting distal pulmonary arteries (PA). These arteries are deformed, leading to right ventricular ...

Chronic Thromboembolic Pulmonary Hypertension and Assessment of Right Ventricular Function in the Piglet

An original piglet model of Chronic Thromboembolic Pulmonary Hypertension (CTEPH) associated with chronic Right Ventricular (RV) dysfunction is described. Pulmonary Hypertension (PH) was induced in 3-week-old piglets by a progressive obstruction of the pulmonary vascular bed. A ligation of the left Pulmonary Artery (PA) was performed first through a mini-thoracotomy. Second, weekly embolizations of the right lower pulmonary lobe were done under fluoroscopic guidance with n-butyl-2-cyanoacrylate during 5 weeks. Mean Pulmonary Arterial Pressure (mPAP) measured by ritght heart catheterism, increased progressively, as well as Right Atrial pressure and Pulmonary Vascular Resistances (PVR) after 5 weeks compared to sham animals. Right Ventricular (RV) structural and functional remodeling were assessed by transthoracic echocardiography (RV diameters, RV wall thickness, RV systolic function). RV elastance and RV-pulmonary coupling were assessed by Pressure-Volume Loops (PVL) analysis with conductance method. Histologic study of the lung and the right ventricle were also performed. Molecular analyses on RV fresh tissues could be performed through repeated transcutaneous endomyocardial biopsies. Pulmonary microvascular disease in obstructed and unobstructed territories was studied from lung biopsies using molecular analyses and pathology. Furthermore, the reliability and the reproducibility was associated with a range of PH severity in animals. Most aspects of the human CTEPH disease were reproduced in this model, which allows new perspectives for the understanding of the underlying mechanisms (mitochondria, inflammation) and new therapeutic approaches (targeted, cellular or gene therapies) of the overloaded right ventricle but also pulmonary microvascular disease.

Chronic Thromboembolic Pulmonary Hypertension (CTEPH) and Right Ventricular (RV) dysfunction were induced in piglets by progressive obstruction of the pulmonary arteries. Consequences were remarkably similar to those observed in CTEPH patients. This animal model would be a very useful tool for pathophysiology and therapeutic experiments on CTEPH and RV failure.

An original piglet model of Chronic Thromboembolic Pulmonary Hypertension (CTEPH) associated with chronic Right Ventricular (RV) dysfunction is described. ...

Hemodynamic Characterization of Rodent Models of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary vasculature characterized by endothelial cell apoptosis, smooth muscle proliferation and obliteration of pulmonary arterioles. This in turn results in right ventricular (RV) failure, with significant morbidity and mortality. Rodent models of PAH, in the mouse and the rat, are important for understanding the pathophysiology underlying this rare disease. Notably, different models of PAH may be associated with different degrees of pulmonary hypertension, RV hypertrophy and RV failure. Therefore, a complete hemodynamic characterization of mice and rats with PAH is critical in determining the effects of drugs or genetic modifications on the disease. 
Here we demonstrate standard procedures for assessment of right ventricular function and hemodynamics in both rat and mouse PAH models. Echocardiography is useful in determining RV function in rats, although obtaining standard views of the right ventricle is challenging in the awake mouse. Access for right heart catheterization is obtained by the internal jugular vein in closed-chest mice and rats. Pressures can be measured using polyethylene tubing with a fluid pressure transducer or a miniature micromanometer pressure catheter. Pressure-volume loop analysis can be performed in the open chest. After obtaining hemodynamics, the rodent is euthanized. The heart can be dissected to separate the RV free wall from the left ventricle (LV) and septum, allowing an assessment of RV hypertrophy using the Fulton index (RV/(LV+S)). Then samples can be harvested from the heart, lungs and other tissues as needed.

Pulmonary arterial hypertension (PAH) is a disease of pulmonary arterioles that leads to their obliteration and the development of right ventricular failure. Rodent models of PAH are critical in understanding the pathophysiology of PAH. Here we demonstrate hemodynamic characterization, with right heart catheterization and echocardiography, in the mouse and rat.

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary vasculature characterized by endothelial cell apoptosis, smooth muscle ...

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 ...

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 ...

Left Atrial Stenosis Induced Pulmonary Venous Arterialization and Group 2 Pulmonary Hypertension in Rat

The mechanism of mitral stenosis-induced pulmonary venous arterialization and group 2 pulmonary hypertension (PH) is unclear. There is no rodent model of group 2 PH, due to mitral stenosis (MS), to facilitate the investigation of disease mechanisms and potential therapeutic strategies. We present a novel rat model of pulmonary venous congestion-induced pulmonary venous arterialization and group 2 PH caused by left atrial stenosis (LAS). LAS is achieved by constricting the left atrium using a half-closed titanium clip. After the LAS surgery, a rat model with a transmitral inflow velocity greater than or equal to 2.0 m/s on echocardiography gradually develops pulmonary venous arterialization and group 2 PH over an 8- to 10-week period. In this protocol, we provide the step-by-step procedure of how to perform the LAS surgery. The presented LAS rat model mimics MS in humans and is useful for studying the underlying molecular mechanism of pulmonary venous arterialization and for the preclinical evaluation of therapies for group 2 PH.

Left atrial stenosis (LAS) is a novel surgical technique used for studying group 2 pulmonary hypertension (PH) and mechanisms underlying pulmonary venous arterialization. Here, we present a protocol to constrict the left atrium using a titanium clip to cause pulmonary venous arterialization and moderate PH in a rat.

The mechanism of mitral stenosis-induced pulmonary venous arterialization and group 2 pulmonary hypertension (PH) is unclear. There is no rodent model of ...

Induction and Characterization of Pulmonary Hypertension in Mice using the Hypoxia/SU5416 Model

Pulmonary Hypertension (PH) is a pathophysiological condition, defined by a mean pulmonary arterial pressure exceeding 25 mm Hg at rest, as assessed by right heart&#160;catheterization. A broad spectrum of diseases can lead to PH, differing in their etiology, histopathology, clinical presentation, prognosis, and response to&#160;treatment. Despite significant progress in the last years, PH remains an uncured disease. Understanding the underlying mechanisms can pave the way for the development of new therapies. Animal models are important research tools to achieve this goal. Currently, there are several models available for recapitulating PH. This protocol describes a two-hit mouse PH model. The stimuli for PH development are hypoxia and the injection of SU5416, a vascular endothelial growth factor (VEGF) receptor antagonist. Three weeks after initiation of Hypoxia/SU5416, animals develop pulmonary vascular remodeling imitating the histopathological changes observed in human PH (predominantly Group 1). Vascular remodeling in the pulmonary circulation results in the remodeling of the right&#160;ventricle (RV). The procedures for measuring RV pressures (using the open chest method), the morphometrical analyses of the RV (by dissecting and weighing both cardiac ventricles) and the histological assessments of the remodeling (both pulmonary by assessing vascular remodeling and cardiac by assessing RV cardiomyocyte hypertrophy and fibrosis) are described in detail. The advantages of this protocol are the possibility of the application both in wild type and in genetically modified mice, the relatively easy and low-cost implementation, and the quick development of the disease of interest (3 weeks). Limitations of this method are that mice do not develop a severe phenotype and PH is reversible upon return to normoxia. Prevention, as well as therapy studies, can easily be implemented in this model, without the necessity of advanced skills (as opposed to surgical rodent models).

This protocol describes the induction of pulmonary hypertension (PH) in mice based on the exposure to hypoxia and the injection of a VEGF receptor antagonist. The animals develop PH and right ventricular (RV) hypertrophy 3 weeks after the initiation of the protocol. The functional and morphometrical characterization of the model is also presented.

Pulmonary Hypertension (PH) is a pathophysiological condition, defined by a mean pulmonary arterial pressure exceeding 25 mm Hg at rest, as assessed by ...