Name: evaluation of left ventricular structure and function using 3d echocardiography
Uploaded: 2020-10-28T12:30:00
Description: Watch this Scientific Journal Video about Evaluation of Left Ventricular Structure and Function using 3D Echocardiography at JoVE.com

Project no. NVKP_16-1&#8211;2016-0017 (&#8217;National Heart Program&#8217;) has been implemented with the support provided from the National Research, Development and Innovation Fund of Hungary, financed under the NVKP_16 funding scheme. The research was financed by the Thematic Excellence Programme (2020-4.1.1.-TKP2020) of the Ministry for Innovation and Technology in Hungary, within the framework of the Therapeutic Development and Bioimaging thematic programmes of the Semmelweis University.

This protocol follows the guidelines of the Semmelweis University Regional and Institutional Committee of Science and Research Ethics. The present protocol applies to a specific vendor. Although some steps remain valid regardless of the ultrasound machine and postprocessing software, important differences may exist if using other vendors&#39; solutions.
1. Technical requirements
<ol>
	<li>Utilize an echocardiography machine capable of 3D imaging.</li>
	<li>Connect a 3D transthoracic echocard...

<ol>
	<li>Guta, A. C., 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=Three-dimensional+echocardiography+to+assess+left+ventricular+geometry+and+function.">Three-dimensional echocardiography to assess left ventricular geometry and function.</a> Expert Review of Cardiovascular Therapy. 17 (11), 801-815 (2019).</li><li>Surkova, E., 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=Current+Clinical+Applications+of+Three-Dimensional+Echocardiography:+When+the+Technique+Makes+the+Difference.">Current Clinical Applications of Three-Dimensional Echocardiography: When the Technique Makes the Difference.</a> Current Cardiology Reports. 18 (11), 109 (2016).</li><li>Lang, R. 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=Recommendations+for+cardiac+chamber+quantification+by+echocardiography+in+adults:+an+update+from+the+American+Society+of+Echocardiography+and+the+European+Association+of+Cardiovascular+Imaging.">Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging.</a> Journal of the American Society of Echocardiography. 28 (1), 1-39 (2015).</li><li>Matyas, C., 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=Comparison+of+speckle-tracking+echocardiography+with+invasive+hemodynamics+for+the+detection+of+characteristic+cardiac+dysfunction+in+type-1+and+type-2+diabetic+rat+models.">Comparison of speckle-tracking echocardiography with invasive hemodynamics for the detection of characteristic cardiac dysfunction in type-1 and type-2 diabetic rat models.</a> Cardiovascular Diabetology. 17 (1), 13 (2018).</li><li>Kovacs, 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=Impact+of+hemodialysis,+left+ventricular+mass+and+FGF-23+on+myocardial+mechanics+in+end-stage+renal+disease:+a+three-dimensional+speckle+tracking+study.">Impact of hemodialysis, left ventricular mass and FGF-23 on myocardial mechanics in end-stage renal disease: a three-dimensional speckle tracking study.</a> International Journal of Cardiovascular Imaging. 30 (7), 1331-1337 (2014).</li><li>Muraru, D., 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=Comprehensive+analysis+of+left+ventricular+geometry+and+function+by+three-dimensional+echocardiography+in+healthy+adults.">Comprehensive analysis of left ventricular geometry and function by three-dimensional echocardiography in healthy adults.</a> Journal of the American Society of Echocardiography. 26 (6), 618-628 (2013).</li><li>Lakatos, B. K., 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=Relationship+between+Cardiac+Remodeling+and+Exercise+Capacity+in+Elite+Athletes:+Incremental+Value+of+Left+Atrial+Morphology+and+Function+Assessed+by+Three-Dimensional+Echocardiography.">Relationship between Cardiac Remodeling and Exercise Capacity in Elite Athletes: Incremental Value of Left Atrial Morphology and Function Assessed by Three-Dimensional Echocardiography.</a> Journal of the American Society of Echocardiography. 33 (1), 101-109 (2020).</li><li>Muraru, D., 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=Intervendor+Consistency+and+Accuracy+of+Left+Ventricular+Volume+Measurements+Using+Three-Dimensional+Echocardiography.">Intervendor Consistency and Accuracy of Left Ventricular Volume Measurements Using Three-Dimensional Echocardiography.</a> Journal of the American Society of Echocardiography. 31 (2), 158-168 (2018).</li><li>Kalam, K., Otahal, P., Marwick, T. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prognostic+implications+of+global+LV+dysfunction:+a+systematic+review+and+meta-analysis+of+global+longitudinal+strain+and+ejection+fraction.">Prognostic implications of global LV dysfunction: a systematic review and meta-analysis of global longitudinal strain and ejection fraction.</a> Heart. 100 (21), 1673-1680 (2014).</li><li>Muraru, D., 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=Validation+of+a+novel+automated+border-detection+algorithm+for+rapid+and+accurate+quantitation+of+left+ventricular+volumes+based+on+three-dimensional+echocardiography.">Validation of a novel automated border-detection algorithm for rapid and accurate quantitation of left ventricular volumes based on three-dimensional echocardiography.</a> European Journal of Echocardiography. 11 (4), 359-368 (2010).</li><li>Doronina, 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=The+Female+Athlete's+Heart:+Comparison+of+Cardiac+Changes+Induced+by+Different+Types+of+Exercise+Training+Using+3D+Echocardiography.">The Female Athlete's Heart: Comparison of Cardiac Changes Induced by Different Types of Exercise Training Using 3D Echocardiography.</a> BioMed Research International. 2018, 3561962 (2018).</li><li>Takeuchi, 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=Measurement+of+left+ventricular+mass+by+real-time+three-dimensional+echocardiography:+validation+against+magnetic+resonance+and+comparison+with+two-dimensional+and+m-mode+measurements.">Measurement of left ventricular mass by real-time three-dimensional echocardiography: validation against magnetic resonance and comparison with two-dimensional and m-mode measurements.</a> Journal of the American Society of Echocardiography. 21 (9), 1001-1005 (2008).</li><li>Armstrong, A. C., 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=LV+mass+assessed+by+echocardiography+and+CMR,+cardiovascular+outcomes,+and+medical+practice.">LV mass assessed by echocardiography and CMR, cardiovascular outcomes, and medical practice.</a> JACC Cardiovasc Imaging. 5 (8), 837-848 (2012).</li><li>Olah, 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=Characterization+of+the+dynamic+changes+in+left+ventricular+morphology+and+function+induced+by+exercise+training+and+detraining.">Characterization of the dynamic changes in left ventricular morphology and function induced by exercise training and detraining.</a> International Journal of Cardiology. 277, 178-185 (2019).</li><li>Nagy, V. K., 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=Role+of+Right+Ventricular+Global+Longitudinal+Strain+in+Predicting+Early+and+Long-Term+Mortality+in+Cardiac+Resynchronization+Therapy+Patients.">Role of Right Ventricular Global Longitudinal Strain in Predicting Early and Long-Term Mortality in Cardiac Resynchronization Therapy Patients.</a> PLoS One. 10 (12), e0143907 (2015).</li><li>Kovacs, A., Lakatos, B., Tokodi, M., Merkely, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Right+ventricular+mechanical+pattern+in+health+and+disease:+beyond+longitudinal+shortening.">Right ventricular mechanical pattern in health and disease: beyond longitudinal shortening.</a> Heart Failure Reviews. 24 (4), 511-520 (2019).</li><li>Badano, L. P., 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=Use+of+three-dimensional+speckle+tracking+to+assess+left+ventricular+myocardial+mechanics:+inter-vendor+consistency+and+reproducibility+of+strain+measurements.">Use of three-dimensional speckle tracking to assess left ventricular myocardial mechanics: inter-vendor consistency and reproducibility of strain measurements.</a> European Heart Journal - Cardiovascular Imaging. 14 (3), 285-293 (2013).</li></ol>

LV morphological and functional measurements represent cornerstones of diagnosis, management, and follow-up of cardiac diseases; moreover, they are powerful predictors of outcome. Generally, 2D echocardiography-based evaluation of the LV is recommended by current practice guidelines; however, 3D echocardiography has been proven to be more accurate as it is free from geometrical assumptions concerning LV shape7,8. Deformation imaging by speckle tracking is a robus...

The assessment of left ventricular (LV) morphology and function is the predominant purpose of general and even more specific investigations in cardiology1. The widely available and noninvasive transthoracic echocardiography (TTE), which can provide dense amounts of information, is the method of choice for a convenient, fast, and cost-effective evaluation.
Measurement of LV mass, volumes, and subsequent ejection fraction holds significant diagnostic and also prognostic value2. The more accurate a given measure is, the higher its value will be. A better correlation with gold standard cardiac magnetic resonance (CMR) imaging derived values is an ongoing chase for echocardiographic techniques. Generally, clinical practice guidelines recommend the biplane Simpson&#39;s method for LV volume and ejection fraction measurement3. However, the LV is a three-dimensional (3D) structure with an often irregular shape, and therefore, several tomographic planes will undoubtedly fail in some clinical scenarios to accurately delineate LV morphology and function. Recent advancements in ultrasonic hardware and software technology permitted the development of real-time 3D imaging, which revolutionalizes echocardiographic protocols.
Moreover, the need for a quantitative approach concerning wall motion abnormalities resulted in the rise of deformation imaging4. Strain and strain rate parameters can be calculated by speckle tracking using standard grey-scale images. 3D echocardiography may also overcome several shortcomings of a two-dimensional strain assessment5. From an expensive scientific tool, 3D echocardiography started to become a powerful technique used in everyday clinical practice, and the quantification of the LV is certainly in the first line in this breakthrough.
The present article aims to guide the reader through a detailed 3D protocol by presenting tips and tricks and also by highlighting the potential pitfalls to facilitate the widespread but technically sound use of this important technique concerning the LV.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>3V-D/4V-D/4Vc-D</td>
			<td>General Electric</td>
			<td>n.a.</td>
			<td>ultrasound probe</td>
		</tr>
		<tr>
			<td>4D Auto LVQ</td>
			<td>General Electric</td>
			<td>n.a.</td>
			<td>software for analysis</td>
		</tr>
		<tr>
			<td>E9/E95</td>
			<td>General Electric</td>
			<td>n.a.</td>
			<td>ultrasound machine</td>
		</tr>
		<tr>
			<td>EchoPac v203</td>
			<td>General Electric</td>
			<td>n.a.</td>
			<td>software for analysis</td>
		</tr>
	</tbody>
</table>

evaluation of left ventricular structure and function using 3d echocardiography

Three-dimensional (3D) quantification of the left ventricle (LV) provides significant added value in terms of diagnostic accuracy and precise risk stratification in various cardiac disorders. Recently, 3D echocardiography became available in routine cardiology practice; however, high-quality image acquisition and subsequent analysis have a steep learning curve. The present article aims to guide the reader through a detailed 3D protocol by presenting tips and tricks and also by highlighting the potential pitfalls to facilitate the widespread but technically sound use of this important technique concerning the LV. First and foremost, we show the acquisition of a high-quality 3D dataset with optimal spatial and temporal resolution. Then, we present the analytical steps toward a detailed quantification of the LV by using one of the most widely applied built-in software. We will quantify LV volumes, sphericity, mass and also systolic function by measuring ejection fraction and myocardial deformation (longitudinal and circumferential strain). We will discuss and provide clinical examples about the essential scenarios where the transition from a conventional echocardiographic approach to a 3D-based quantification is highly recommended.

3D analysis of the LV is feasible in the majority of patients. Case 1 is a healthy volunteer with normal ventricular volumes and function (Figure 1). Case 2 (Figure 2) is a 64-year old male patient with dilated cardiomyopathy and a wide QRS complex (160 ms) of left bundle branch block morphology. Gold standard CMR measurements were the following: end-diastolic volume: 243 mL, end-systolic volume: 160 mL, ejection fraction: 34%, L...

Watch this Scientific Journal Video about Evaluation of Left Ventricular Structure and Function using 3D Echocardiography at JoVE.com

Evaluation of Left Ventricular Structure and Function using 3D Echocardiography

In this article, we provide a step-by-step acquisition and analysis protocol for the volumetric assessment and speckle-tracking analysis of the left ventricle by 3D echocardiography, particularly focusing on practical aspects that maximize the feasibility of this technique.

Three-dimensional (3D) quantification of the left ventricle (LV) provides significant added value in terms of diagnostic accuracy and precise risk ...

3D echocardiographic assessment of cardiac structure and function, is a breakthrough innovation in cardiology. Quantification of left ventricle morphology and systolic performance, is the single most important step in every echocardiographic protocol. 3D echocardiographic-derived left ventricular volumes and ejection fraction correlate the most with core standard cardiac MRI and have shown to be more reproducible compared with conventional 2D techniques.More accurate results, turn into more tailored therapeutic decisions and that the end of the day, better patient outcomes. The scientific and clinical success of 3D based left ventricle assessment, paves the way to apply a similar technique to other cardiac structures such as right ventricle, the atria or even the valves. Proper image acquisition, followed by a comprehensive critical image analysis are the prerequisites for adequate use and accurate measurements.Our video article provides a step-by-step guide to achieve this. For the acquisition of 3D echocardiographic images, position the patient in the left lateral decubitus position and confirm that the ECG tracing on the screen is of good quality. Unfreeze the image and begin to examine the patient with the transducer, to visualize as a conventional apical four chamber view.To optimize the image quality, adjust the sector width to the left ventricle, lowering the depth to truncate the left atrium and using a slight over gain. Press the 4D button to switch to 3D mode and acquire 3D images in the multi or single-beat mode. Use the multi-beat mode to achieve a higher spatial and temporal resolution, from which the dataset will be reconstructed from two, three, four or six cardiac cycles.Obtain an end expiratory breath hold of the patient, maintaining the stable transducer positioning, to minimize the stitching artifacts. When the full volume is reconstructed from the sub-volumes and entire left ventricle is visible, freeze the image again. And using the cycle select and number of cycles knobs, select the optimal acquired cardiac cycles and press image store.For left ventricle morphology and function quantification, select a 3D data set appropriate for analysis and click measure and volume. Select 4D Auto LVQ. On the quad screen, the software will ask, modify alignment of apical slices to standard views?Correct the apical views manually as necessary by tilting and rotation, to obtain the corresponding standard view and thereby eliminating foreshortening. Drag and move the calipers on the long axis views to set the tilting to align the caliper with the long axis of the left ventricle and use the corresponding or rotate all knobs or adjust the calipers on the short axis image to set the rotation. After finishing the view alignment, click to the end-diastolic volume.For semiautomatic detection of the left ventricle endo and epicardial surface, select two landmark points manually on any apical views and successively identify the left ventricle apex and the middle of the left ventricle base in any apical view. The algorithm will automatically contour the endocardial border of the entire left ventricle. Check contour credibility in three apical views, three short axis views of different levels and a fourth user controlled short axis, to allow visual verification of the detected surface.Then proceed to and measure the end-systolic volume as just demonstrated for the end-diastolic volume, to identify and correct the endocardial contour on the end-systolic frame. Next, proceed to volume wave form. The software will display a dynamic 3D model of the left ventricle and a time volume curve as it traces the endocardial surface throughout the cardiac cycle frame by frame.Proceed to the left ventricle mass measurement. The software will automatically contour the left ventricle epicardial contour on the end-diastolic frame, and calculate the left ventricle mass. Click to assess the 4D strain region of interest.The software will automatically contour epicardial surface on the end-systolic frame, and calculate the left ventricle and systolic mass. Finally, click 4D strain results. The software will visualize the 3D myocardial tracking on multiple short and long axis planes and the corresponding strain values of the 17 standard left ventricle segments throughout the cardiac cycle frame by frame.Time strain curves and a bullseye plot will be displayed. The longitudinal, circumferential, radial and area strains, rotation and torsion, will also be calculated and can be demonstrated. Then to terminate the analysis, click approve and exit.Here, a 3D analysis of the left ventricle in a healthy volunteer with normal ventricular volumes and function, is shown. This 3D left ventricle analysis of a 64 year old male patient, shows a dilated cardiomyopathy and a wide QRS complex of the left bundle branch block morphology. The analysis of myocardial mechanics by 3D speckle tracking, provides meaningful data on dyssynchronous contractions and segmental dysfunction.When attempting this protocol, keep in mind that despite all these advancements in trans-user and software technology, a good quality image of the heart is necessary to achieve accurate results. 3D echocardiographic assessment of ventricle structure and function is no longer just a scientific toy. It is ready for everyday when called prime time.

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Research

JoVE Journal

Bioengineering

Measuring Left Ventricular Pressure in Late Embryonic and Neonatal Mice

Blood pressure increases significantly during embryonic and postnatal development in vertebrate animals. In the mouse, blood flow is first detectable around embryonic day (E) 8.51. Systolic left ventricular (LV) pressure is 2 mmHg at E9.5 and 11 mmHg at E14.52. At these mid-embryonic stages, the LV is clearly visible through the chest wall for invasive pressure measurements because the ribs and skin are not fully developed. Between E14.5 and birth (approximately E21) imaging methods must be used to view the LV. After birth, mean arterial pressure increases from 30 - 70 mmHg from postnatal day (P) 2 - 353. Beyond P20, arterial pressure can be measured with solid-state catheters (i.e. Millar or Scisense). Before P20, these catheters are too big for developing mouse arteries and arterial pressure must be measured with custom pulled plastic catheters attached to fluid-filled pressure transducers3 or glass micropipettes attached to servo null pressure transducers4.
Our recent work has shown that the greatest increase in blood pressure occurs during the late embryonic to early postnatal period in mice5-7. This large increase in blood pressure may influence smooth muscle cell (SMC) phenotype in developing arteries and trigger important mechanotransduction events. In human disease, where the mechanical properties of developing arteries are compromised by defects in extracellular matrix proteins (i.e. Marfan's Syndrome8 and Supravalvular Aortic Stenosis9) the rapid changes in blood pressure during this period may contribute to disease phenotype and severity through alterations in mechanotransduction signals. Therefore, it is important to be able to measure blood pressure changes during late embryonic and neonatal periods in mouse models of human disease.
We describe a method for measuring LV pressure in late embryonic (E18) and early postnatal (P1 - 20) mice. A needle attached to a fluid-filled pressure transducer is inserted into the LV under ultrasound guidance. Care is taken to maintain normal cardiac function during the experimental protocol, especially for the embryonic mice. Representative data are presented and limitations of the protocol are discussed.

Measuring left ventricular pressure (LV) in embryonic and neonatal mice is described. Pressure is measured by inserting a needle connected to a fluid-filled transducer into the LV under ultrasound guidance. Care must be taken to maintain normal cardiac function during the experimental protocol.

Blood pressure increases significantly during embryonic and postnatal development in vertebrate animals. In the mouse, blood flow is first detectable ...

In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that MicroCT provides quantitative high-resolution three-dimensional (3D) anatomical data non-destructively and longitudinally. Most importantly, with the development of a novel preclinical iodinated contrast agent called eXIA160, functional and metabolic assessment of the heart became possible. However, prior to the advent of commercial MicroCT scanners equipped with X-ray flat-panel detector technology and easy-to-use cardio-respiratory gating, preclinical studies of cardiovascular disease (CVD) in small animals required a MicroCT technologist with advanced skills, and thus were impractical for widespread implementation. The goal of this work is to provide a practical guide to the use of the high-speed Quantum FX MicroCT system for comprehensive determination of myocardial global and regional function along with assessment of myocardial perfusion, metabolism and viability in healthy mice and in a cardiac ischemia mouse model induced by permanent occlusion of the left anterior descending coronary artery (LAD).

In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

This method outlines the use of Quantum Micro-Computed Tomography (MicroCT) to assess cardiac morphology, function, perfusion, metabolism and viability with iodinated contrast agent in mice with experimentally-induced myocardial ischemia. The technique can be applied for non-destructive high-throughput longitudinal in vivo imaging of various animal models of human heart disease.

The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that ...

Improving 2D and 3D Skin In Vitro Models Using Macromolecular Crowding

The glycoprotein family of collagens represents the main structural proteins in the human body, and are key components of biomaterials used in modern tissue engineering. A technical bottleneck is the deposition of collagen in vitro, as it is notoriously slow, resulting in sub-optimal formation of connective tissue and subsequent tissue cohesion, particularly in skin models. Here, we describe a method which involves the addition of differentially-sized sucrose co-polymers to skin cultures to generate macromolecular crowding (MMC), which results in a dramatic enhancement of collagen deposition. Particularly, dermal fibroblasts deposited a significant amount of collagen I/IV/VII and fibronectin under MMC in comparison to controls.
The protocol also describes a method to decellularize crowded cell layers, exposing significant amounts of extracellular matrix (ECM) which were retained on the culture surface as evidenced by immunocytochemistry. Total matrix mass and distribution pattern was studied using interference reflection microscopy. Interestingly, fibroblasts, keratinocytes and co-cultures produced cell-derived matrices (CDM) of varying composition and morphology. CDM could be used as &#34;bio-scaffolds&#34; for secondary cell seeding, where the current use of coatings or scaffolds, typically from xenogenic animal sources, can be avoided, thus moving towards more clinically relevant applications.
In addition, this protocol describes the application of MMC during the submerged phase of a 3D-organotypic skin co-culture model which was sufficient to enhance ECM deposition in the dermo-epidermal junction (DEJ), in particular, collagen VII, the major component of anchoring fibrils. Electron microscopy confirmed the presence of anchoring fibrils in cultures developed with MMC, as compared to controls. This is significant as anchoring fibrils tether the dermis to the epidermis, hence, having a pre-formed mature DEJ may benefit skin graft recipients in terms of graft stability and overall wound healing. Furthermore, culture time was condensed from 5 weeks to 3 weeks to obtain a mature construct, when using MMC, reducing costs.

Improving 2D and 3D Skin In Vitro Models Using Macromolecular Crowding

We present a protocol to obtain cell-derived matrices rich in extracellular matrix proteins, using macromolecular crowders (MMC). In addition, we present a protocol which incorporates MMC in 3D organotypic skin co-culture generation, which reduces culture time while maintaining maturity of construct.

The glycoprotein family of collagens represents the main structural proteins in the human body, and are key components of biomaterials used in modern ...

Bioprinting of Cartilage and Skin Tissue Analogs Utilizing a Novel Passive Mixing Unit Technique for Bioink Precellularization

Bioprinting is a powerful technique for the rapid and reproducible fabrication of constructs for tissue engineering applications. In this study, both cartilage and skin analogs were fabricated after bioink pre-cellularization utilizing a novel passive mixing unit technique. This technique was developed with the aim to simplify the steps involved in the mixing of a cell suspension into a highly viscous bioink. The resolution of filaments deposited through bioprinting necessitates the assurance of uniformity in cell distribution prior to printing to avoid the deposition of regions without cells or retention of large cell clumps that can clog the needle. We demonstrate the ability to rapidly blend a cell suspension with a bioink prior to bioprinting of both cartilage and skin analogs. Both tissue analogs could be cultured for up to 4 weeks. Histological analysis demonstrated both cell viability and deposition of tissue specific extracellular matrix (ECM) markers such as glycosaminoglycans (GAGs) and collagen I respectively.

Cartilage and skin analogs were bioprinted using a nanocellulose-alginate based bioink. The bioinks were cellularized prior to printing via a single step passive mixing unit. The constructs were demonstrated to be uniformly cellularized, have high viability, and exhibit favorable markers of differentiation.

Bioprinting is a powerful technique for the rapid and reproducible fabrication of constructs for tissue engineering applications. In this study, both ...

Purification and Analytics of a Monoclonal Antibody from Chinese Hamster Ovary Cells Using an Automated Microbioreactor System

Monoclonal antibodies (mAbs) are one of the most popular and well-characterized biological products manufactured today. Most commonly produced using Chinese hamster ovary (CHO) cells, culture and process conditions must be optimized to maximize antibody titers and achieve target quality profiles. Typically, this optimization uses automated microscale bioreactors (15 mL) to screen multiple process conditions in parallel. Optimization criteria include culture performance and the critical quality attributes (CQAs) of the monoclonal antibody (mAb) product, which may impact its efficacy and safety. Culture performance metrics include cell growth and nutrient consumption, while the CQAs include the mAb's N-glycosylation and aggregation profiles, charge variants, and molecular weight. This detailed protocol describes how to purify and subsequently analyze HCCF samples produced by an automated microbioreactor system to gain valuable performance metrics and outputs. First, an automated protein A fast protein liquid chromatography (FPLC) method is used to purify the mAb from harvested cell culture samples. Once concentrated, the glycan profiles are analyzed by mass spectrometry using a specific platform (refer to the Table of Materials). Antibody molecular weights and aggregation profiles are determined using size exclusion chromatography-multiple angle light scattering (SEC-MALS), while charge variants are analyzed using microchip capillary zone electrophoresis (mCZE). In addition to the culture performance metrics captured during the bioreactor process (i.e., culture viability, cell counts, and common metabolites including glutamine, glucose, lactate, and ammonia), spent media is analyzed to identify limiting nutrients to improve the feeding strategies and overall process design. Therefore, a detailed protocol for the absolute quantification of amino acids by liquid chromatography-mass spectrometry (LC-MS) of spent media is also described. The methods used in this protocol take advantage of high-throughput platforms that are compatible for large numbers of small-volume samples.

A detailed protocol for the purification and subsequent analysis of a monoclonal antibody from harvested cell culture fluid (HCCF) of automated microbioreactors has been described. Use of analytics to determine critical quality attributes (CQAs) and maximizing limited sample volume to extract vital information is also presented.

Monoclonal antibodies (mAbs) are one of the most popular and well-characterized biological products manufactured today. Most commonly produced using ...

Four-Dimensional CT Analysis Using Sequential 3D-3D Registration

Four-dimensional computed tomography (4DCT) provides a series of volume data and visualizes joint motions. However, numerical analysis of 4DCT data remains difficult because segmentation in all volumetric frames is time-consuming. We aimed to analyze joint kinematics using a sequential 3D-3D registration technique to provide the kinematics of the moving bone with respect to the fixed bone semiautomatically using 4DCT DICOM data and existing software. Surface data of the source bones are reconstructed from 3DCT. The trimmed surface data are respectively matched with surface data from the first frame in 4DCT. These trimmed surfaces are sequentially matched until the last frame. These processes provide positional information for target bones in all frames of the 4DCT. Once the coordinate systems of the target bones are decided, translation and rotation angles between any two bones can be calculated. This 4DCT analysis offers advantages in kinematic analyses of complex structures such as carpal or tarsal bones. However, fast or large-scale motions cannot be traced because of motion artifacts.

We analyzed joint kinematics from four-dimensional computed tomography data. The sequential 3D-3D registration method semiautomatically provides the kinematics of the moving bone with respect to the subject bone from four-dimensional computed tomography data.

Four-dimensional computed tomography (4DCT) provides a series of volume data and visualizes joint motions. However, numerical analysis of 4DCT data ...

Optical Imaging of Isolated Murine Ventricular Myocytes

The ability to isolate adult cardiac myocytes has permitted researchers to study a variety of cardiac pathologies at the single cell level. While advances in calcium sensitive dyes have permitted the robust optical recording of single cell calcium dynamics, recording of robust transmembrane optical voltage signals has remained difficult. Arguably, this is because of the low single to noise ratio, phototoxicity, and photobleaching of traditional potentiometric dyes. Therefore, single cell voltage measurements have long been confined to the patch clamp technique which while the gold standard, is technically demanding and low throughput. However, with the development of novel potentiometric dyes, large, fast optical responses to changes in voltage can be obtained with little to no phototoxicity and photobleaching. This protocol describes in detail how to isolate adult murine myocytes which can be used for cellular shortening, calcium, and optical voltage measurements. Specifically, the protocol describes how to use a ratiometric calcium dye, a single-excitation calcium dye, and a single excitation voltage dye. This approach can be used to assess the cardiotoxicity and arrhythmogenicity of various chemical agents. While phototoxicity is still an issue at the single cell level, methodology is discussed on how to reduce it.

We present the methodology for the isolation of murine myocytes and how to obtain voltage or calcium traces simultaneously with sarcomere shortening traces using fluorescence photometry with simultaneous digital cell geometry measurements.

The ability to isolate adult cardiac myocytes has permitted researchers to study a variety of cardiac pathologies at the single cell level. While advances ...

Primary Clarification of CHO Harvested Cell Culture Fluid using an Acoustic Separator

Primary clarification is an essential step in a biomanufacturing process for the initial removal of cells from therapeutic products within the harvested cell culture fluid. While traditional methods like centrifugation or filtration are widely implemented for cell removal, the equipment for these processes have large footprints and operation can involve contamination risks and filter fouling. Additionally, traditional methods may not be ideal for continuous bioprocessing schemes for primary clarification. Thus, an alternate application using acoustic (sound) waves was investigated to continuously separate cells from the cell culture fluid. Presented in this study is a detailed protocol for using a bench-scale acoustic wave separator (AWS) for the primary separation of culture fluid containing a monoclonal IgG1 antibody from a CHO cell bioreactor harvest. Representative data are presented from the AWS and demonstrate how to achieve effective cell clarification and product recovery. Finally, potential applications for AWS in continuous bioprocessing are discussed. Overall, this study provides a practical and general protocol for the implementation of AWS in primary clarification for CHO cell cultures and further describes its application potential in continuous bioprocessing.

Presented here is a protocol for the primary clarification of CHO cell culture using an acoustic separator. This protocol can be used for the primary clarification of shake flask cultures or bioreactor harvests and has the potential application for continuous clarification of the cell bleed material during perfusion bioreactor operations.

Primary clarification is an essential step in a biomanufacturing process for the initial removal of cells from therapeutic products within the harvested ...

Quantification of Mouse Heart Left Ventricular Function, Myocardial Strain, and Hemodynamic Forces by Cardiovascular Magnetic Resonance Imaging

Mouse models have contributed significantly to understanding genetic and physiological factors involved in healthy cardiac function, how perturbations result in pathology, and how myocardial diseases may be treated. Cardiovascular magnetic resonance imaging (CMR) has become an indispensable tool for a comprehensive in vivo assessment of cardiac anatomy and function. This protocol shows detailed measurements of mouse heart left ventricular function, myocardial strain, and hemodynamic forces using 7-Tesla CMR. First, animal preparation and positioning in the scanner are demonstrated. Survey scans are performed for planning imaging slices in various short- and long-axis views. A series of prospective ECG-triggered short-axis (SA) movies (or CINE images) are acquired covering the heart from apex to base, capturing end-systolic and end-diastolic phases. Subsequently, single-slice, retrospectively gated CINE images are acquired in a midventricular SA view, and in 2-, 3-, and 4-chamber views, to be reconstructed into high-temporal resolution CINE images using custom-built and open-source software. CINE images are subsequently analyzed using dedicated CMR image analysis software.
Delineating endomyocardial and epicardial borders in SA end-systolic and end-diastolic CINE images allows for the calculation of end-systolic and end-diastolic volumes, ejection fraction, and cardiac output. The midventricular SA CINE images are delineated for all cardiac time frames to extract a detailed volume-time curve. Its time derivative allows for the calculation of the diastolic function as the ratio of the early filling and atrial contraction waves. Finally, left ventricular endocardial walls in the 2-, 3-, and 4-chamber views are delineated using feature-tracking, from which longitudinal myocardial strain parameters and left ventricular hemodynamic forces are calculated. In conclusion, this protocol provides detailed in vivo quantification of the mouse cardiac parameters, which can be used to study temporal alterations in cardiac function in various mouse models of heart disease.

This study describes a comprehensive cardiovascular magnetic resonance imaging (CMR) protocol to quantify the left ventricular functional parameters of the mouse heart. The protocol describes the acquisition, post-processing, and analysis of the CMR images as well as assessment of different cardiac functional parameters.

Mouse models have contributed significantly to understanding genetic and physiological factors involved in healthy cardiac function, how perturbations ...

A Large Animal Model for Pulmonary Hypertension and Right Ventricular Failure: Left Pulmonary Artery Ligation and Progressive Main Pulmonary Artery Banding in Sheep

Decompensated right ventricular failure (RVF) in pulmonary hypertension (PH) is fatal, with limited medical treatment options. Developing and testing novel therapeutics for PH requires a clinically relevant large animal model of increased pulmonary vascular resistance and RVF. This manuscript discusses the latest development of the previously published ovine PH-RVF model that utilizes left pulmonary artery (PA) ligation and main PA occlusion. This model of PH-RVF is a versatile platform to control not only the disease severity but also the RV&#39;s phenotypic response.
Adult sheep (60-80 kg) underwent left PA (LPA) ligation, placement of main PA cuff, and insertion of RV pressure monitor. PA cuff and RV pressure monitor were connected to subcutaneous ports. Subjects underwent progressive PA banding twice per week for 9 weeks with sequential measures of RV pressure, PA cuff pressures, and mixed venous blood gas (SvO2). At the initiation and endpoint of this model, ventricular function and dimensions were assessed using echocardiography. In a representative group of 12 animal subjects, RV mean and systolic pressure increased from 28 &#177; 5 and 57 &#177; 7 mmHg at week 1, respectively, to 44 &#177; 7 and 93 &#177; 18 mmHg (mean &#177; standard deviation) by week 9. Echocardiography demonstrated characteristic findings of PH-RVF, notably RV dilation, increased wall thickness, and septal bowing. The longitudinal trend of SvO2 and PA cuff pressure demonstrates that the rate of PA banding can be titrated to elicit varying RV phenotypes. A faster PA banding strategy led to a precipitous decline in SvO2 &#60; 65%, indicating RV decompensation, whereas a slower, more paced strategy led to the maintenance of physiologic SvO2 at 70%-80%. One animal that experienced the accelerated strategy developed several liters of pleural effusion and ascites by week 9. This chronic PH-RVF model provides a valuable tool for studying molecular mechanisms, developing diagnostic biomarkers, and enabling therapeutic innovation to manage RV adaptation and maladaptation from PH.

This manuscript describes the surgical technique and experimental approach to develop severe right ventricular pressure overload to model their adaptive and maladaptive phenotypes.

Decompensated right ventricular failure (RVF) in pulmonary hypertension (PH) is fatal, with limited medical treatment options. Developing and testing ...