Die Autoren bedanken sich bei Shad Schipke und Daniel Chesser für ihre Hilfe bei der Konstruktion und Fertigung des Systems und Valtresa Myles für die Unterstützung bei der Erstellung des Manuskripts.

1. Tissue Ernte und Zubereitung <ol><li> Aortenklappen sollte von ausgewachsenen Schweinen mit einem Gewicht von nicht mehr als £ 120 unmittelbar nach dem Tod gesammelt werden. </li><li> Waschen Sie die Ventile zweimal mit steriler Phosphat-gepufferter Kochsalzlösung (PBS) und Transport ins Labor auf Eis. </li><li> Alle weiteren Schritte sollten unter sterilen Bedingungen durchgeführt werden. </li><li> Stellen Sie sicher, dass Flugblätter zeigen keine Anzeichen von Degeneration, Reißen oder Verkalkung. Entfernen Sie Prospekte von der Aortenwurzel, indem 1 / 3 des Abstandes von der Ring. </li><li> Ort Flugblätter in einzelnen Vertiefungen einer sechs-Well-Platte und inkubieren mit 3ml Dulbeccos Modified Eagle Medium mit 1% anti-biotic/anti-mycotic-Lösung und 10% fötalem Rinderserum bei 37 ° C und 5% CO 2 ergänzt Nacht. </li><li> Als Alternative isolierten Zellen lassen sich in sechs-well-Platten ausgesät werden und in der Druck-Gerät. Isolation des Ventils Endothelzellen und interstitiellen Zellen kann wie bisher 13, 14 beschrieben werden. </li></ol> 2. Pressure Studies <ol><li> Eine maßgeschneiderte Druck-System wurde entwickelt, um die mechanobiological Auswirkungen von zyklischen Druck auf Aortenklappe Gewebe 15 zu studieren. </li><li> Melden Sie sich an den Computer und öffnen Sie die LabVIEW-Programm (Abbildung 1). </li><li> Kalibrierung: <ol><li> Vor Experimenten, sollte das System korrekt kalibriert werden. </li><li> Schließen Sie das Netzteil an die Platine. Dieser versorgt die Magnetventile, dass der Luftstrom in und aus der Kammer zu steuern. </li><li> Achten Sie darauf, die Druckluft an das System angeschlossen ist, und öffnen Sie die Luftzufuhr in voller Geschwindigkeit. </li><li> Schalten Sie den Signalverstärker. Achten Sie darauf, die Spannung zu lesen ist 0,00. Passen Sie bei Bedarf </li><li> Die LabVIEW-Schnittstelle verfügt über einen Schalter mit der Aufschrift &quot;TEST / RECORD&quot;. Sicherstellen, dass die Schalter auf &quot;TEST&quot;. Klicken Sie auf die Schaltfläche mit der Aufschrift &quot;Air Supply&quot; mit dem Einlass-Magnetventil geöffnet. </li><li> Mit dem Gas-Druckregler, Druck der Kammer mit Druckluft bei 1 PSI. Der Druck in der Kammer kann mit dem digitalen Manometer an der hinteren Endplatte der Kammer befinden. Sobald der Druck äquilibriert, notieren Sie die Spannung Lesung aus dem Signalverstärker. Wiederholen Sie für 2, 3, 4 und 5 PSI. </li><li> Konstruieren Sie eine Eichkurve Druck vs Spannung. Der Druck sollte von PSI zu mmHg umgewandelt werden. Die Gleichung von der Grafik kann in den Code der LabVIEW-Programm platziert werden </li></ol></li><li> Entfernen Sie die Aluminium-Frontplatte aus der Druckkammer und besprühen Sie die Kammer mit 70% Ethanol. Lassen Sie für ein Minimum von 10 Minuten, damit Restethanol Dämpfe zu zerstreuen. </li><li> Legen Sie die Sechs-Well-Platte mit dem Flugblatt Proben in der Kammer und ersetzen Sie die vordere Endplatte. Sicherstellen, dass die Dichtung luftdicht ist durch Anziehen der Muttern auf die vier Gewindestangen (befindet sich an jeder Ecke der Endplatte) von Hand entfernt. Legen Sie die Druckkammer in der 37 ° C Inkubator. Eine schematische Darstellung der Druckkammer ist in Abbildung 2 dargestellt. </li><li> Die Schnittstelle wird der Benutzer aufgefordert, die Zeit, das System Zyklen zwischen Druckluft-und Ausgang bietet. Diese sollten auf 0,6 Sekunden und 0,4 Sekunden zu imitieren diastolischen und systolischen Bedingungen bzw. bei einer Frequenz von 1 Hz eingestellt werden. Der Benutzer sollte auch einen Datei-Pfad. </li><li> In LabVIEW, klicken Sie laufen und schalten Sie den &quot;TEST / RECORD&quot; toggle auf &quot;RECORD&quot;. </li><li> Vergewissern Sie sich, der Druck auf dem gewünschten Niveau mit der Grafik auf der LabVIEW-Schnittstelle. Der Druck kann mit dem Gasdruckregler werden. </li><li> Run-Programm für die gewünschte Länge der Zeit. </li><li> Nachdem das Experiment abgeschlossen ist, klicken Sie auf die Stopp-Taste auf LabVIEW, schalten Sie Luftzufuhr und öffnen Sie das Auslassventil auf der Druckkammer. </li><li> Entfernen Sie die vordere Endplatte aus der Kammer und Abrufen von sechs Well-Platte mit Proben. Muster können ab sofort für die Genexpression, Proteinexpression, Histologie, mechanische Eigenschaften usw. analysiert werden </li></ol> 3. Repräsentative Ergebnisse: Der Druck ist für die Simulation maximale transvalvuläre Drücke unter normotensiven beobachtet, Stufe I und Stufe II hypertensive Bedingungen. Allerdings war der Druck nicht in der Lage, den systolischen Druckgradienten, die im wesentlichen Null ist in vivo nachahmen. Die Frequenz ist bei 1 Hz erhalten, mit einem Lufteinlass Zeit 0.6s und eine Abgas-Zeit von 0,4 Sekunden. Vertreter Druckkurven von normalen und erhöhten Druck Bedingungen aus dem System erhalten können in Bild 3 zu sehen. <img src="/files/ftp_upload/3316/3316fig1.jpg" alt="Abbildung 1"/> Abbildung 1: Screenshot der LabVIEW-Schnittstelle. <img src="/files/ftp_upload/3316/3316fig2.jpg" alt="Abbildung 2"/> Abbildung 2: Schematische Darstellung der Druckkammer A. Isometrische Ansicht der Druckkammer; B. Seitenansicht der Druckkammer;C. Draufsicht Druckkammer. <img src="/files/ftp_upload/3316/3316fig3.jpg" alt="Abbildung 3"/> Abbildung 3: Graph der Druck-Simulation in der Druckkammer bei (A) normotensiven, (B) Stadium I hypertensive und (C) Stufe II hypertensive Bedingungen.

<ol>
	<li>Freeman, R. V., Otto, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spectrum+of+calcific+aortic+valve+disease:+pathogenesis,+disease+progression,+and+treatment+strategies.">Spectrum of calcific aortic valve disease: pathogenesis, disease progression, and treatment strategies.</a> Circulation. 111, 3316-3326 (2005).</li><li>Robicsek, F., Thubrikar, M. J., Fokin, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cause+of+degenerative+disease+of+the+trileaflet+aortic+valve:+review+of+subject+and+presentation+of+a+new+theory.">Cause of degenerative disease of the trileaflet aortic valve: review of subject and presentation of a new theory.</a> Ann Thorac Surg. 73, 1346-1354 (2002).</li><li>Thubrikar, M. J., Aouad, J., Nolan, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patterns+of+calcific+deposits+in+operatively+excised+stenotic+or+purely+regurgitant+aortic+valves+and+their+relation+to+mechanical+stress.">Patterns of calcific deposits in operatively excised stenotic or purely regurgitant aortic valves and their relation to mechanical stress.</a> Am J Cardiol. 58, 304-308 (1986).</li><li>Agno, F. S., Chinali, M., Bella, J. N., Liu, J. E., Arnett, D. K., Kitzman, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aortic+valve+sclerosis+is+associated+with+preclinical+cardiovascular+disease+in+hypertensive+adults:+the+Hypertension+Genetic+Epidemiology+Network+study.">Aortic valve sclerosis is associated with preclinical cardiovascular disease in hypertensive adults: the Hypertension Genetic Epidemiology Network study.</a> J Hypertens. 23, 867-8673 (2005).</li><li>Cawley, P. J., Otto, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prevention+of+calcific+aortic+valve+stenosis+-+fact+or+fiction.">Prevention of calcific aortic valve stenosis - fact or fiction.</a> Annals of Medicine. 41, 100-108 (2009).</li><li>Durst, C. A., Grande-Allen, J. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+and+physical+characterization+of+a+synchronous+multivalve+aortic+valve+culture+system.">Design and physical characterization of a synchronous multivalve aortic valve culture system.</a> Ann Biomed Eng. 38, 319-3125 (2010).</li><li>Engelmayr, G. C., Soletti, L., Vigmostad, S. C., Budilarto, S. G., Federspiel, W. J., Chandran, K. B. <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+flex-stretch-flow+bioreactor+for+the+study+of+engineered+heart+valve+tissue+mechanobiology.">A novel flex-stretch-flow bioreactor for the study of engineered heart valve tissue mechanobiology.</a> Ann Biomed Eng. 36, 700-712 (2008).</li><li>Sucosky, P., Padala, M., Elhammali, A., Balachandran, K., Jo, H., Yoganathan, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+of+an+ex+vivo+culture+system+to+investigate+the+effects+of+shear+stress+on+cardiovascular+tissue.">Design of an ex vivo culture system to investigate the effects of shear stress on cardiovascular tissue.</a> J Biomech Eng. 130, 035001-03 (2008).</li><li>Syedain, Z. H., Tranquillo, R. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlled+cyclic+stretch+bioreactor+for+tissue-engineered+heart+valves.">Controlled cyclic stretch bioreactor for tissue-engineered heart valves.</a> Biomaterials. 30, 4078-4084 (2009).</li><li>Lagana, K., Moretti, M., Dubini, G., Raimondi, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+bioreactor+for+the+controlled+application+of+complex+mechanical+stimuli+for+cartilage+tissue+engineering.">A new bioreactor for the controlled application of complex mechanical stimuli for cartilage tissue engineering.</a> Proc Inst Mech Eng H. 222, 705-715 (2008).</li><li>Wartella, K. A., Wayne, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioreactor+for+biaxial+mechanical+stimulation+to+tissue+engineered+constructs.">Bioreactor for biaxial mechanical stimulation to tissue engineered constructs.</a> J Biomech Eng. 131, 044501-044501 (2009).</li><li>Wallis, M. C., Yeger, H., Cartwright, L., Shou, Z., Radisic, M., Haig, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Feasibility+study+of+a+novel+urinary+bladder+bioreactor.">Feasibility study of a novel urinary bladder bioreactor.</a> Tissue Eng Part A. 14, 339-348 (2008).</li><li>Butcher, J. T., Nerem, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Valvular+endothelial+cells+regulate+the+phenotype+of+interstitial+cells+in+co-culture:+effects+of+steady+shear+stress.">Valvular endothelial cells regulate the phenotype of interstitial cells in co-culture: effects of steady shear stress.</a> Tissue Eng. 12, 905-915 (2006).</li><li>Metzler, S. A., Pregonero, C. A., Butcher, J. T., Burgess, S. C., Warnock, J. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cyclic+Strain+Regulates+Pro-Inflammatory+Protein+Expression+in+Porcine+Aortic+Valve+Endothelial+Cells.">Cyclic Strain Regulates Pro-Inflammatory Protein Expression in Porcine Aortic Valve Endothelial Cells.</a> J Heart Valve Dis. 17, 571-578 (2008).</li><li>Schipke, 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=.">.</a> Design of a cyclic pressure bioreactor for the ex vivo study of aortic heart valve mechanobiology. , (2008).</li><li>Smith, K. E., Metzler, S. A., Warnock, J. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cyclic+strain+inhibits+acute+pro-inflammatory+gene+expression+in+aortic+valve+interstitial+cells.">Cyclic strain inhibits acute pro-inflammatory gene expression in aortic valve interstitial cells.</a> Biomechanics and Modeling in Mechanobiology. , (2009).</li><li>Warnock, J. N., Burgess, S. C., Shack, A., Yoganathan, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+immediate-early+gene+responses+to+elevated+pressure+in+porcine+aortic+valve+interstitial+cells.">Differential immediate-early gene responses to elevated pressure in porcine aortic valve interstitial cells.</a> J Heart Valve Dis. 15, 34-41 (2006).</li><li>Brathwaite, D., Weissman, C. <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+onset+of+atrial+arrhythmias+following+major+noncardiothoracic+surgery+is+associated+with+increased+mortality.">The new onset of atrial arrhythmias following major noncardiothoracic surgery is associated with increased mortality.</a> Chest. 114, 462-468 (1998).</li><li>Walsh, S. R., Oates, J. E., Anderson, J. A., Blair, S. D., Makin, C. A., Walsh, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postoperative+arrhythmias+in+colorectal+surgical+patients:+incidence+and+clinical+correlates.">Postoperative arrhythmias in colorectal surgical patients: incidence and clinical correlates.</a> Colorectal Dis. 8, 212-216 (2006).</li><li>Walsh, S. R., Tang, T., Gaunt, M. E., Schneider, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+arrhythmias+after+non-cardiothoracic+surgery.">New arrhythmias after non-cardiothoracic surgery.</a> BMJ. 7, 333-333 (2006).</li><li>Walsh, S. R., Tang, T., Wijewardena, C., Yarham, S. I., Boyle, J. R., Gaunt, M. 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Keine Interessenskonflikte erklärt.

Der Druck-System erfolgreich Aortenklappensegel zyklische Belastungen, die Vertreter der diastolische Druck transvalvuläre ausgesetzt waren. Allerdings war es nicht möglich, systolische Druck transvalvuläre imitieren, da der Druck nur sank auf 40 mmHg. Transvalvuläre Druck ist der Unterschied zwischen dem Druck in der Aorta ascendens und des linken Ventrikels. Während der Diastole, wenn das Ventil geschlossen ist, wird die Druckdifferenz unter normotensiven Bedingungen und 90 mmHg 80mmHg und 100 mmHg im Stadium I u...

<table border="1"><tbody><tr><th> Name des Reagenzes </th><th> Firma </th><th> Katalog-Nummer </th><th> Kommentare (optional) </th></tr><tr><td> DMEM </td><td> Sigma </td><td> D5671 </td><td></td></tr><tr><td> Dulbecco PBS </td><td> Sigma </td><td> D5652 </td><td></td></tr><tr><td> Anti-mycotic/antibiotic Lösung </td><td> Sigma </td><td> A5955 </td><td></td></tr><tr><td> Fetal Bovine Serum </td><td> ThermoScientific </td><td> SH30070 </td><td></td></tr><tr><td> Viton-Membran-Magnetventile </td><td> McMaster Carr </td><td> 4868K11 </td><td></td></tr><tr><td> Druckaufnehmer </td><td> Omega Engineering, Inc. </td><td> PX302-200GV </td><td></td></tr><tr><td> Wägezelle conditioner </td><td> Encore Electronics, Inc. </td><td> 4025-101 </td><td></td></tr><tr><td> Data Acquisition (DAQ) Module </td><td> Measurement Computing </td><td> PMD1608 </td><td></td></tr></tbody></table>

design of a cyclic pressure bioreactor for the ex vivo study of aortic heart valves

Die Aortenklappe zwischen der linken Herzkammer und der Aorta befindet, ermöglicht die unidirektionale Durchblutung und verhindert Rückfluss in die Herzkammer. Aortenklappensegel sind der interstitiellen Zellen innerhalb einer extrazellulären Matrix (ECM) suspendiert und mit einer endothelialen Monolayer gesäumt zusammen. Das Ventil hält eine harte, dynamischen Umfeld und ist ständig zu scheren, Flexion, Spannung und Kompression ausgesetzt. Die Forschung hat calcific Läsionen in erkrankten gezeigten Ventile kommen in Bereichen mit hoher mechanischer Belastung als Folge der endothelialen Störung oder interstitielle Matrix Schaden 1-3. Daher ist es nicht verwunderlich, dass epidemiologische Studien haben hohen Blutdruck, eine führende Risikofaktor bei der Entstehung von Aortenvitien 4 dargestellt. Die einzige Behandlungsmöglichkeit, die jetzt bei Herzklappenerkrankungen ist die chirurgische Ersatz des erkrankten Ventil mit einem bioprothetischen oder mechanische Ventil 5. Verbessertes Verständnis des Ventils Biologie in Reaktion auf körperliche Belastungen helfen würde, Aufklärung der Mechanismen der Pathogenese Ventil. Im Gegenzug könnte dies in der Entwicklung von nicht-invasive Therapien wie pharmazeutische Intervention oder Prävention zu helfen. Mehrere Bioreaktoren wurden bereits entwickelt, um die Mechanobiologie von nativen oder Herzklappen 6-9 studieren. Pulsierende Bioreaktoren sind auch entwickelt worden, um einer Reihe von Geweben einschließlich Knorpel 10, 11 und Knochen Blase 12 zu studieren. Das Ziel dieser Arbeit war es, eine zyklische Druck-System, verwendet, um die biologische Reaktion der Aortenklappensegel zu einer erhöhten Druckbelastung klären könnten zu entwickeln. Das System bestand aus einem Acryl-Kammer, in der Proben Ort und produzieren zyklische Druck, Viton Membrane Magnetventile, um das Timing der Druck Zyklus zu steuern, und einen Computer, um elektrische Geräte zu steuern. Der Druck wurde unter Verwendung eines Druckaufnehmer, und das Signal war bedingt durch eine Kraftmessdose Conditioner. Ein LabVIEW-Programm reguliert den Druck mit einem analogen Gerät mit Druckluft ins System zu pumpen an der entsprechenden Rate. Das System imitiert die dynamische transvalvuläre Druckniveaus mit der Aortenklappe verbunden, eine Sägezahnwelle produziert eine schrittweise Erhöhung des Drucks, die typisch für die transvalvuläre Druckverlauf, der derzeit über dem Ventil ist während der Diastole, durch einen scharfen Druckabfall darstellt Ventilöffnung in gefolgt Systole. Die LabVIEW-Programm erlaubt Benutzern, das Ausmaß und die Häufigkeit der zyklische Druck zu kontrollieren. Das System war in der Lage, um Gewebeproben zu physiologischen und pathologischen Druckverhältnissen unterworfen. Dieses Gerät kann verwendet werden, um unser Verständnis, wie Herzklappen, um Änderungen in der lokalen mechanischen Umfeld zu reagieren erhöhen.

Watch this Scientific Journal Video about Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves at JoVE.com

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

Eine zyklische Druck Bioreaktor in der Lage zu unterwerfen Herzklappengewebe zu physiologischen und pathologischen Druckverhältnisse ausgelegt ist. Ein LabVIEW-Programm ermöglicht es Benutzern, Druck Größe, Amplitude und Frequenz-Steuerung. Dieses Gerät kann verwendet werden, um die Mechanobiologie der Herzklappe Gewebe oder isolierte Zellen zu studieren.

Entwurf eines zyklischen Druck Bioreaktor für die Ex Vivo Studium der Aorten-Herzklappen

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic ...

design-cyclic-pressure-bioreactor-for-ex-vivo-study-aortic-heart

Research

Education

JoVE Core

JoVE Journal

Physics

Bioengineering

Unit 1

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

Sources of Magnetic Fields

SCIENTISTS IN ACTION

15.6K Aufrufe.  Mississippi State University. Eine zyklische Druck Bioreaktor in der Lage zu unterwerfen Herzklappengewebe zu physiologischen und pathologischen Druckverhältnisse ausgelegt ist. Ein LabVIEW-Programm ermöglicht es Benutzern, Druck Größe, Amplitude und Frequenz-Steuerung. Dieses Gerät kann verwendet werden, um die Mechanobiologie der Herzklappe Gewebe oder isolierte Zellen zu studieren.

Serie: Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

Patient-specific Modeling of the Heart: Estimation of Ventricular Fiber Orientations

Patient-specific simulations of heart (dys)function aimed at personalizing cardiac therapy are hampered by the absence of in vivo imaging technology for clinically acquiring myocardial fiber orientations. The objective of this project was to develop a methodology to estimate cardiac fiber orientations from in vivo images of patient heart geometries. An accurate representation of ventricular geometry and fiber orientations was reconstructed, respectively, from high-resolution ex vivo structural magnetic resonance (MR) and diffusion tensor (DT) MR images of a normal human heart, referred to as the atlas. Ventricular geometry of a patient heart was extracted, via semiautomatic segmentation, from an in vivo computed tomography (CT) image. Using image transformation algorithms, the atlas ventricular geometry was deformed to match that of the patient. Finally, the deformation field was applied to the atlas fiber orientations to obtain an estimate of patient fiber orientations. The accuracy of the fiber estimates was assessed using six normal and three failing canine hearts. The mean absolute difference between inclination angles of acquired and estimated fiber orientations was 15.4 &deg;. Computational simulations of ventricular activation maps and pseudo-ECGs in sinus rhythm and ventricular tachycardia indicated that there are no significant differences between estimated and acquired fiber orientations at a clinically observable level.The new insights obtained from the project will pave the way for the development of patient-specific models of the heart that can aid physicians in personalized diagnosis and decisions regarding electrophysiological interventions.

A methodology to estimate ventricular fiber orientations from in vivo images of patient heart geometries for personalized modeling is described. Validation of the methodology performed using normal and failing canine hearts demonstrate that that there are no significant differences between estimated and acquired fiber orientations at a clinically observable level.

Patienten-spezifischer Modellierung des Herz: Schätzung der Ventrikuläre Faserorientierungen

Patient-specific  simulations of heart (dys)function aimed at personalizing cardiac therapy are hampered  by the absence of in vivo imaging technology for ...

Forschung

Biotechnik

Design of a Biaxial Mechanical Loading Bioreactor for Tissue Engineering

We designed a loading device that is capable of applying uniaxial or biaxial mechanical strain to a tissue engineered biocomposites fabricated for transplantation. While the device primarily functions as a bioreactor that mimics the native mechanical strains, it is also outfitted with a load cell for providing force feedback or mechanical testing of the constructs. The device subjects engineered cartilage constructs to biaxial mechanical loading with great precision of loading dose (amplitude and frequency) and is compact enough to fit inside a standard tissue culture incubator. It loads samples directly in a tissue culture plate, and multiple plate sizes are compatible with the system. The device has been designed using components manufactured for precision-guided laser applications. Bi-axial loading is accomplished by two orthogonal stages. The stages have a 50 mm travel range and are driven independently by stepper motor actuators, controlled by a closed-loop stepper motor driver that features micro-stepping capabilities, enabling step sizes of less than 50 nm. A polysulfone loading platen is coupled to the bi-axial moving platform. Movements of the stages are controlled by Thor-labs Advanced Positioning Technology (APT) software. The stepper motor driver is used with the software to adjust load parameters of frequency and amplitude of both shear and compression independently and simultaneously. Positional feedback is provided by linear optical encoders that have a bidirectional repeatability of 0.1 &mu;m and a resolution of 20 nm, translating to a positional accuracy of less than 3 &mu;m over the full 50 mm of travel. These encoders provide the necessary position feedback to the drive electronics to ensure true nanopositioning capabilities. In order to provide the force feedback to detect contact and evaluate loading responses, a precision miniature load cell is positioned between the loading platen and the moving platform. The load cell has high accuracies of 0.15% to 0.25% full scale.

We designed a novel mechanical loading bioreactor that can apply uniaxial or biaxial mechanical strain to a cartilage biocomposite prior to transplantation into an articular cartilage defect.

Entwurf eines Biaxiale Mechanische Belastung Bioreaktor für Tissue Engineering

We  designed a loading device that is capable of applying uniaxial or biaxial  mechanical strain to a tissue engineered biocomposites fabricated for  ...

Operation of a Benchtop Bioreactor

Fermentation systems are used to provide an optimal growth environment for many different types of cell cultures. The ability afforded by fermentors to carefully control temperature, pH, and dissolved oxygen concentrations in particular makes them essential to efficient large scale growth and expression of fermentation products. This video will briefly describe the advantages of the fermentor over the shake flask. It will also identify key components of a typical benchtop fermentation system and give basic instruction on setup of the vessel and calibration of its probes. The viewer will be familiarized with the sterilization process and shown how to inoculate the growth medium in the vessel with culture. Basic concepts of operation, sampling, and harvesting will also be demonstrated. Simple data analysis and system cleanup will also be discussed.

Fermentors are used to increase culture yield and productivity of bioengineered cells. After screening multiple microbial or animal cell culture candidates in shake flasks, the next logical step is to increase the selected culture&#x2019;s biomass with the fermentor. This video demonstrates the setup and operation of a typical benchtop bioreactor system.

Betrieb einer Tischbioreaktor

Fermentation systems are used to provide an optimal growth environment for many different types of cell cultures. The ability afforded by fermentors to ...

Characterization of Complex Systems Using the Design of Experiments Approach: Transient Protein Expression in Tobacco as a Case Study

Plants provide multiple benefits for the production of biopharmaceuticals including low costs, scalability, and safety. Transient expression offers the additional advantage of short development and production times, but expression levels can vary significantly between batches thus giving rise to regulatory concerns in the context of good manufacturing practice. We used a design of experiments (DoE) approach to determine the impact of major factors such as regulatory elements in the expression construct, plant growth and development parameters, and the incubation conditions during expression, on the variability of expression between batches. We tested plants expressing a model anti-HIV monoclonal antibody (2G12) and a fluorescent marker protein (DsRed). We discuss the rationale for selecting certain properties of the model and identify its potential limitations. The general approach can easily be transferred to other problems because the principles of the model are broadly applicable: knowledge-based parameter selection, complexity reduction by splitting the initial problem into smaller modules, software-guided setup of optimal experiment combinations and step-wise design augmentation. Therefore, the methodology is not only useful for characterizing protein expression in plants but also for the investigation of other complex systems lacking a mechanistic description. The predictive equations describing the interconnectivity between parameters can be used to establish mechanistic models for other complex systems.

We describe a design of experiments approach that can be used to determine and model the influence of transgene regulatory elements, plant growth and development parameters, and incubation conditions on the transient expression of monoclonal antibodies and reporter proteins in plants.

Charakterisierung komplexer Systeme Mit dem Design of Experiments Ansatz: Transient Protein Expression in Tabak als Case Study

Plants provide multiple benefits for the production of biopharmaceuticals including low costs, scalability, and safety. Transient expression offers the ...

Anatomically Realistic Neonatal Heart Model for Use in Neonatal Patient Simulators

Neonatal patient simulators (NPS) are artificial patient surrogates used in the context of medical simulation training. Neonatologists and nursing staff practice clinical interventions such as chest compressions to ensure patient survival in the case of bradycardia or cardiac arrest. The simulators used currently are of low physical fidelity and therefore cannot provide qualitative insight into the procedure of chest compressions. The embedding of an anatomically realistic heart model in future simulators enables the detection of cardiac output generated during chest compressions; this can provide clinicians with an output parameter, which can deepen the understanding of the effect of the compressions in relation to the amount of blood flow generated. Before this monitoring can be achieved, an anatomically realistic heart model must be created containing: two atria, two ventricles, four heart valves, pulmonary veins and arteries, and systemic veins and arteries. This protocol describes the procedure for creating such a functional artificial neonatal heart model by utilizing a combination of magnetic resonance imaging (MRI), 3D printing, and casting in the form of cold injection molding. Using this method with flexible 3D printed inner molds in the injection molding process, an anatomically realistic heart model can be obtained.

This protocol describes a procedure for creating functional artificial neonatal heart models by utilizing a combination of magnetic resonance imaging, 3D printing, and injection molding. The purpose of these models is for integration into the next generation of neonatal patient simulators and as a tool for physiological and anatomical studies.

Anatomisch realistischen neonatale Herzmodell für den Einsatz bei Neugeborenen Patienten Simulatoren

Neonatal patient simulators (NPS) are artificial patient surrogates used in the context of medical simulation training. Neonatologists and nursing staff ...

Light-sheet Fluorescence Microscopy for the Study of the Murine Heart

Light-sheet fluorescence microscopy has been widely used for rapid image acquisition with a high axial resolution from micrometer to millimeter scale. Traditional light-sheet techniques involve the use of a single illumination beam directed orthogonally at sample tissue. Images of large samples that are produced using a single illumination beam contain stripes or artifacts and suffer from a reduced resolution due to the scattering and absorption of light by the tissue. This study uses a dual-sided illumination beam and a simplified CLARITY optical clearing technique for the murine heart. These techniques allow for deeper imaging by removing lipids from the heart and produce a large field of imaging, greater than 10 x 10 x 10 mm3. As a result, this strategy enables us to quantify the ventricular dimensions, track the cardiac lineage, and localize the spatial distribution of cardiac-specific proteins and ion-channels from the post-natal to adult mouse hearts with sufficient contrast and resolution.

This study uses a dual-sided illumination light-sheet fluorescence microscopy (LSFM) technique combined with optical clearing to study the murine heart.

Licht-Blatt Fluoreszenzmikroskopie for the Study of Murine Herzen

Light-sheet fluorescence microscopy has been widely used for rapid image acquisition with a high axial resolution from micrometer to millimeter scale. ...

A New Ex Vivo Model for the Evaluation of Endoscopic Submucosal Injection Material Performance

Increasing the performance of submucosal injection materials (SIMs) is important for endoscopic therapy of early gastrointestinal cancer. It is essential to establish an ex vivo model that can evaluate SIM performance accurately, for developing high-performance SIMs. In our previous study, we developed a new ex vivo model that can be used to evaluate the performance of various SIMs in detail by applying constant tension to the specimen&#39;s ends. We also confirmed that the proposed new ex vivo model allows accurate submucosal elevation height (SEH) measurement under uniform conditions and detailed comparisons of the performances of various types of SIMs. Here, we describe the new ex vivo model and explain the detailed setup methodology of this model. Since all parts of the new model were easy to obtain, the setup of the new model could be completed quickly. SEH of various SIMs could be measured more accurately by using the new model. The critical factor that determines SIM performance can be identified using the new model. SIM development speed will drastically increase after the factor has been identified.

A New Ex Vivo Model for the Evaluation of Endoscopic Submucosal Injection Material Performance

We developed a new ex vivo model that applies constant tension to the porcine gastric specimen. This development made it possible to evaluate the performance (the height and duration of the submucosal elevation) of various SIMs accurately.&#160; The detailed setup methodology of this new model is explained.

Ein neues Ex Vivo Modell für die Bewertung der endoskopischen Submucosal Einspritzung Materialverhalten

Increasing the performance of submucosal injection materials (SIMs) is important for endoscopic therapy of early gastrointestinal cancer. It is essential ...

Biaxial Mechanical Characterizations of Atrioventricular Heart Valves

Extensive biaxial mechanical testing of the atrioventricular heart valve leaflets can be utilized to derive&#160;optimal parameters used in constitutive models, which provide a mathematical representation of the mechanical function of those structures. This presented biaxial mechanical testing protocol involves (i) tissue acquisition, (ii) the preparation of tissue specimens, (iii) biaxial mechanical testing, and (iv) postprocessing of the acquired data. First, tissue acquisition requires obtaining porcine or ovine hearts from a local Food and Drug Administration-approved abattoir for later dissection to retrieve the valve leaflets. Second, tissue preparation requires using tissue specimen cutters on the leaflet tissue to extract a clear zone for testing. Third, biaxial mechanical testing of the leaflet specimen requires the use of a commercial biaxial mechanical tester, which consists of force-controlled, displacement-controlled, and stress-relaxation testing protocols to characterize the leaflet tissue&#39;s mechanical properties. Finally, post-processing requires the use of data image correlation techniques and force and displacement readings to summarize the tissue&#39;s mechanical behaviors in response to external loading. In general, results from biaxial testing demonstrate that the leaflet tissues yield a nonlinear, anisotropic mechanical response. The presented biaxial testing procedure is advantageous to other methods since the method presented here allows for a more comprehensive characterization of the valve leaflet tissue under one unified testing scheme, as opposed to separate testing protocols on different tissue specimens. The proposed testing method has its limitations in that shear stress is potentially present in the tissue sample. However, any potential shear is presumed negligible.

This protocol involves characterizations of atrioventricular valve leaflets with force-controlled, displacement-controlled, and stress-relaxation biaxial mechanical testing procedures. Results acquired with this protocol can be used for constitutive model development to simulate the mechanical behavior of functioning valves under a finite element simulation framework.

Biaxiale mechanische Charakterisierung von ventrikulären Herzklappen

Extensive biaxial mechanical testing of the atrioventricular heart valve leaflets can be utilized to derive&#160;optimal parameters used in constitutive ...

A Friction Testing-Bioreactor Device for Study of Synovial Joint Biomechanics, Mechanobiology, and Physical Regulation

In primary osteoarthritis (OA), normal 'wear and tear' associated with aging inhibits the ability of cartilage to sustain its load-bearing and lubrication functions, fostering a deleterious physical environment. The frictional interactions of articular cartilage and synovium may influence joint homeostasis through tissue level wear and cellular mechanotransduction. To study these mechanical and mechanobiological processes, a device capable of replicating the motion of the joint is described. The friction testing device controls the delivery of reciprocal translating motion and normal load to two contacting biological counterfaces. This study adopts a synovium-on-cartilage configuration, and friction coefficient measurements are presented for tests performed in a phosphate-buffered saline (PBS) or synovial fluid (SF) bath. The testing was performed for a range of contact stresses, highlighting the lubricating properties of SF under high loads. This friction testing device can be used as a biomimetic bioreactor for studying the physical regulation of living joint tissues in response to applied physiologic loading associated with diarthrodial joint articulation.

The present protocol describes a friction testing device that applies simultaneous reciprocal sliding and normal load to two contacting biological counterfaces.

Ein Reibungsprüf-Bioreaktorgerät zur Untersuchung der Synovialgelenksbiomechanik, Mechanobiologie und physikalischen Regulation

In primary osteoarthritis (OA), normal 'wear and tear' associated with aging inhibits the ability of cartilage to sustain its load-bearing and lubrication ...

Procurement and Decellularization of Rat Hindlimbs Using an Ex Vivo Perfusion-Based Bioreactor for Vascularized Composite Allotransplantation

Patients with severe traumatic injuries and tissue loss require complex surgical reconstruction. Vascularized composite allotransplantation (VCA) is an evolving reconstructive avenue for transferring multiple tissues as a composite subunit. Despite the promising nature of VCA, the long-term immunosuppressive requirements are a significant limitation due to the increased risk of malignancies, end-organ toxicity, and opportunistic infections. Tissue engineering of acellular composite scaffolds is a potential alternative in reducing the need for immunosuppression. Herein, the procurement of a rat hindlimb and its subsequent decellularization using sodium dodecyl sulfate (SDS) is described. The procurement strategy presented is based upon the common femoral artery. A machine perfusion-based bioreactor system was constructed and used for ex vivo decellularization of the hindlimb. Successful perfusion decellularization was performed, resulting in a white translucent-like appearance of the hindlimb. An intact, perfusable, vascular network throughout the hindlimb was observed. Histological analyses showed the removal of nuclear contents and the preservation of tissue architecture across all tissue compartments.

Procurement and Decellularization of Rat Hindlimbs Using an Ex Vivo Perfusion-Based Bioreactor for Vascularized Composite Allotransplantation

We describe the surgical technique and decellularization process for composite rat hindlimbs. Decellularization is conducted using low-concentration sodium dodecyl sulfate through an ex vivo machine perfusion system.

Beschaffung und Dezellularisierung von Rattenhinterbeinen mit einem Ex-vivo-Perfusions-basierten Bioreaktor für die vaskularisierte Komposit-Allotransplantation

Patients with severe traumatic injuries and tissue loss require complex surgical reconstruction. Vascularized composite allotransplantation (VCA) is an ...