Diese Arbeit wurde von NSFC Projekte (81522023, 81530059, 91639113, 81772000, 81371699 und 81401534) finanziell unterstützt.

Die Verwendung von Versuchstieren wurde genehmigt durch das Tier Experimente ethischen Ausschuss der Nankai-Universität und durchgeführt in Übereinstimmung mit der Anleitung zur Pflege und Verwendung von Labortieren.
(1) die Herstellung von Electrospun PCL Grafts
Hinweis: Hier wurde eine Elektrospinnen-Technik eingesetzt, um vaskuläre Transplantate zu fabrizieren.
<ol><li>PCL-Lösungen von 25 Gew.-% bis 10 Gew.-%, durch Auflösen von PCL in einer Mischung aus Methanol und Chloroform, bzw. vorbereiten (1:5-Volumen-Verhältnis), bei Raumtemperatur (RT) für 12 h.</li>
	<li>Laden Sie die PCL-Lösung in ein 10 mL Glasspritze.</li>
	<li>Legen Sie die Spritze mit einer 21-G-Nadel.</li>
	<li>Die Sammlung Instrument den Edelstahl-Dorn (2 mm Durchmesser, 25 cm Länge) auflegen.</li>
	<li>Für dickere Fasern Transplantate zu verwenden, die PCL-Lösung von 25 Gew.-%, Arbeitsabstand von 17 cm von der Spitze der Nadel an Sammler, Durchfluss von 8 mL/h, und Spannung von 11 kV als die Elektrospinnen Parameter. Für dünnere Faser Transplantate, verwenden die PCL-Lösung von 10 Gew.-%, Arbeitsabstand von 20 cm von der Nadelspitze an Sammler, einer Durchflussmenge von 2 mL/h, und Spannung von 18 kV als die Elektrospinnen Parameter.</li>
	<li>Sicherstellen Sie, dass die gewonnenen Grafts im Vakuum über Nacht, das restliche Lösungsmittel entfernen platziert sind. Alle Instrumente vor dem Eingriff zu sterilisieren und aseptischen Technik im gesamten pflegen.</li>
	<li>Desinfizieren Sie vor der Implantation die Transplantate durch Eintauchen in 10 mL von 75 % Ethanol für 30 min und sie dann über Nacht mit UV-Licht aussetzen.</li>
	<li>Faser und Pore größenmessungen: Berechnung der durchschnittlichen Faserdurchmesser mit ImageJ-Software basierend auf Rasterelektronenmikroskopie (SEM) Bilder scannen.</li>
	<li>Mechanische Prüfung von Gerüsten:<ol>
<li>Geschnitten Sie die röhrenförmigen Gerüste in Abschnitte 3 mm in der Länge mit einer Rasierklinge. Messen Sie die Stärke von Gerüsten mit einem Mikrometer.</li>
		<li>Legen Sie die röhrenförmigen Gerüste auf einem Zugversuch Rechner mit einer Tragfähigkeit von 100 N.</li>
		<li>Klemmen Sie die Gerüste mit einer 1 mm zwischen Klemme Distanz und ziehen längs mit einer Rate von 10 mm/min bis zum Bruch. Messen Sie die Zugfestigkeit und Bruchdehnung ultimative. Berechnen des Elastizitätsmoduls aus der ersten linearen Region (bis zu 5 % Dehnung) der Spannungs-Dehnungs-Kurve.</li>
	</ol>
</li>
</ol>(2) Bauchaorta Implantation Rattenmodell
Hinweis: Alle Materialien und Instrumente in der Chirurgie sind steril. Während der Operation stellen Sie sicher, dass der Betreiber trägt eine Gaze Maske und sterile Handschuhe um Infektionen zu vermeiden. Stellen Sie sicher, dass die Raumtemperatur bei 27-30 ° C, die tierischen Körper Temperatur gehalten wird. Richtlinien Sie lokale IACUC zur Analgesie.
<ol><li>Verwenden Sie männliche Sprague-Dawley Ratten mit einem Gewicht von 240-270 g als Empfänger der Gefäßprothese. Stellen Sie sicher, dass die Ratte 24 h vor der Operation gefastet hat. Die fastenden Ratten für 24 h soll leer der Kot im Darm-Trakt ausreichend, damit der Bediener Horizont erweitern.</li>
	<li>Die Ratte in den Nacken fassen und halten Sie ihren Kopf nach unten, Springe Nadel in die Bauchhöhle des Unterleibs. Induzieren Sie die Ratte für die Anästhesie mit Chloral Hydrate (330 mg/kg) durch eine intraperitoneale Injektion.</li>
	<li>Bestätigen Sie angemessene Anesthetization, indem sichergestellt wird, dass die Ratte Muskeln und stetige Atmung entspannt hat. Legen Sie die Ratte unter dem Operationsmikroskop in Rückenlage.</li>
	<li>Gelten Sie Vaseline Augenheilkunde Tierarzt Salbe auf die Augen, Trockenheit während der Narkose zu verhindern. Antikoagulation (100 UI/kg) Rute Vene Injektion vor der Operation mit heparinisierten physiologischer Kochsalzlösung (50 UI/mL) verwalten.</li>
	<li>Das Fell in der vorderen Bauchwand mit einer Rasierklinge rasieren Sie ab, und reinigen Sie die Haut mit Jod-Lösung und medizinischem Alkohollösung.</li>
	<li>Führen Sie einen Mittellinie Laparotomie Schnitt mit chirurgische Scheren und sorgen dafür, dass der Schnitt ca. 4-5 cm lang ist und dann setzen die Bauchhöhle.</li>
	<li>Einfahren Sie und wickeln Sie den Darm mit Gaze bevorzugt mit Salzlösung befeuchtet.</li>
	<li>Die Bauchaorta sorgfältig zu sezieren.</li>
	<li>Identifizieren Sie und verbinden Sie alle kleine Äste mit 9-0 Monofilament Nylon Nähte.</li>
	<li>Klemmen Sie den isolierten Abschnitt (bis zu 1 cm Länge) der Aorta mit zwei vaskulären Schellen. Die Aorta kann eingespannten für 20-30 Minuten bleiben.</li>
	<li>Transekt bauchschlagader zwischen zwei Klemmen mit Mikro-Schere, um die Anastomosen Websites zu erstellen.</li>
	<li>Spülen Sie die beiden Enden der Aorta mit heparinisierten Kochsalzlösung (50 UI/mL) um das restliche Blut zu entfernen.</li>
	<li>Die Adventitia mit Mikro-Schere abziehen.</li>
	<li>Anastomosieren Sie das Transplantat mit 2 mm Innendurchmesser und 1 cm in der Länge, die Ratte bauchschlagader mit einem 8er-Naht-Muster mit 9-0 Monofilament Nylon Nähte.</li>
	<li>Zuerst konstruieren Sie vier Anastomosen entsprechend der Reihenfolge der 9, 3, 12 und 06:00-Positionen an der proximalen Seite zu, dann anastomosieren Sie die Schnittkanten in 4 Maschen zwischen zwei Nähte. Nach Beendigung der proximalen Naht, Naht der distalen Seite nach der gleichen Methode. Hinweis: Jeder Stich ist erforderlich, um sicherzustellen, dass die systemeigene Seite leicht in das Transplantat eingebettet ist.</li>
	<li>Die distalen Klammer um das Blut zu fließen in das Transplantat zu ermöglichen, dann entfernen Sie die proximale Klemme.</li>
	<li>Drücken Sie die Fadenenden zu stoppen die Blutung ein steriler Wattebausch oder einem kleinen Gaze Schwamm. Drücken Sie für ca. 3 min bis Blutstillung.</li>
	<li>Den Darm in die Bauchhöhle zurück.</li>
	<li>Spülen Sie die Bauchhöhle mit warmer physiologischer Kochsalzlösung mit Gentamicin (320 U/mL).</li>
	<li>Die Bauchdecke mit einer 3: 0-Nylon-Naht in der Muskeln und Haut Schicht bzw. vernähen.</li>
	<li>Die Ratte in einem sauberen und trockenen Käfig legen Sie und ein Heizkissen unter den Käfig zu tierischen Körpertemperatur aufrechtzuerhalten; dann warten Sie, bis die Ratte aus der Narkose zu erholen. Kümmern Sie sich um das Tier, bis es ausreichend Bewusstsein zur Aufrechterhaltung der sternalen liegen wiedererlangt hat.</li>
	<li>Nachdem er das Bewusstsein wiedererlangt, setzen Sie die Ratte in einem einzigen Käfig mit Futter und Wasser. Gelten Sie Jod auf die Wunde zur Vorbeugung von Infektionen nach der Operation. Die Ratte, die Gesellschaft anderer Tiere zurück, bis es vollständig erholt hat.</li>
	<li>Ratten nach institutionellen Richtlinien zu vorgegebenen Zeitpunkten einschläfern.</li>
</ol>

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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=Femtosecond+laser+ablation+enhances+cell+infiltration+into+three-dimensional+electrospun+scaffolds.">Femtosecond laser ablation enhances cell infiltration into three-dimensional electrospun scaffolds.</a> Acta Biomaterialia. 8 (7), 2648-2658 (2012).</li><li>Rnjak-Kovacina, J., Weiss, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increasing+the+pore+size+of+electrospun+scaffolds.">Increasing the pore size of electrospun scaffolds.</a> Tissue Eng Part B Rev. 17 (5), 365-372 (2011).</li><li>Zhong, S., Zhang, Y., Lim, C. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+of+large+pores+in+electrospun+nanofibrous+scaffolds+for+cellular+infiltration:+a+review.">Fabrication of large pores in electrospun nanofibrous scaffolds for cellular infiltration: a review.</a> Tissue Eng Part B Rev. 18 (2), 77-87 (2012).</li><li>Pham, Q. P., Sharma, U., Mikos, A. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrospun+poly(epsilon-caprolactone)+microfiber+and+multilayer+nanofiber/microfiber+scaffolds:+characterization+of+scaffolds+and+measurement+of+cellular+infiltration.">Electrospun poly(epsilon-caprolactone) microfiber and multilayer nanofiber/microfiber scaffolds: characterization of scaffolds and measurement of cellular infiltration.</a> Biomacromolecules. 7 (10), 2796-2805 (2006).</li><li>Rnjak-Kovacina, J., 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=Tailoring+the+porosity+and+pore+size+of+electrospun+synthetic+human+elastin+scaffolds+for+dermal+tissue+engineering.">Tailoring the porosity and pore size of electrospun synthetic human elastin scaffolds for dermal tissue engineering.</a> Biomaterials. 32 (28), 6729-6736 (2011).</li><li>Wang, Z., 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+effect+of+thick+fibers+and+large+pores+of+electrospun+poly(epsilon-caprolactone)+vascular+grafts+on+macrophage+polarization+and+arterial+regeneration.">The effect of thick fibers and large pores of electrospun poly(epsilon-caprolactone) vascular grafts on macrophage polarization and arterial regeneration.</a> Biomaterials. 35 (22), 5700-5710 (2014).</li><li>Hutcheson, J. 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=Genesis+and+growth+of+extracellular-vesicle-derived+microcalcification+in+atherosclerotic+plaques.">Genesis and growth of extracellular-vesicle-derived microcalcification in atherosclerotic plaques.</a> Nat Mater. 15 (3), 335-343 (2016).</li><li>Tara, S., 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=Well-organized+neointima+of+large-pore+poly(L-lactic+acid)+vascular+graft+coated+with+poly(L-lactic-co-epsilon-caprolactone)+prevents+calcific+deposition+compared+to+small-pore+electrospun+poly(L-lactic+acid)+graft+in+a+mouse+aortic+implantation+model.">Well-organized neointima of large-pore poly(L-lactic acid) vascular graft coated with poly(L-lactic-co-epsilon-caprolactone) prevents calcific deposition compared to small-pore electrospun poly(L-lactic acid) graft in a mouse aortic implantation model.</a> Atherosclerosis. 237 (2), 684-691 (2014).</li></ol>

Die Autoren haben keine finanziellen widerstreitenden Interessen.

Zelle Infiltration ist entscheidend für die Erneuerung und Umbau der Gefäßprothese in Vivo16. Begrenzte Zelle eindringen bezieht sich oft auf die relativ kleinen Poren des Transplantats, die die Migration von Zellen in der Transplantat Wand behindern. Um dieses Problem zu beheben, entwickelten wir eine modifizierte Methode um Electrospun PCL vascular Grafts mit großen Porenstruktur vorzubereiten. Im einzelnen stiegen die Porengröße mit der Zunahme der Dicke Faser, die leicht von den...

Vaskuläre Transplantate aus synthetischen Polymeren hergestellt werden allgemein in Klinik für die Therapie von Herz-Kreislauf-Erkrankungen (CVDs) eingesetzt. Leider, bei kleinem Durchmesser vascular Grafts (D < 6 mm) gibt es keine erfolgreiche Produkte aufgrund der niedrigen Durchgängigkeit, ausgelöst durch reduzierte Blut Strömungsgeschwindigkeit, führt oft zu Thrombose und der Intima-Hyperplasie Komplikationen-1.
Gewebe-Engineering bietet eine alternative Strategie zur langfristigen Durchgängigkeit und Homöostase basierend auf einem Gerüst-geführte vaskuläre Regeneration und Wiederaufbau zu realisieren. Im Detail, die Gefäßprothese als dreidimensionale Vorlage könnte bieten mechanische Unterstützung und strukturelle Führung während der Regeneration der Aderhaut und Einfluss zelluläre Funktionen, einschließlich der Zelladhäsion, Migration, Verbreitung, und Sekretion der extrazellulären Matrix2. Bisher wurden verschiedene synthetische Polymere für Anwendungen in der Aderhaut Technik bewertet. Unter dieser Polymere ist poly(ε-caprolactone) (PCL) Aufgrund guter Handy-Kompatibilität und langsamer Abbau von mehreren Monaten bis hin zu zwei Jahren3intensiv untersucht worden. In einer Ratte Aorta Modell4,5,6, PCL vaskulären Transplantate durch Elektrospinnen verarbeitet ausgestellt hervorragende strukturelle Integrität und Durchgängigkeit, sowie möglichst kontinuierlich erhöhten ZELLINVASION und Neovaskularisation in der Transplantat Wand für bis zu 6 Monaten. Jedoch unerwünschte Gewebe Umbau, einschließlich Regression von Zellen und Kapillaren und Verkalkung, auch beobachtet an längeren Zeitpunkten bis zu 18 Monaten.
Cellularization von der Gefäßprothese ist ein Schlüsselfaktor Bestimmung der Geweberegeneration und7umformt. Elektrospinnen, wurde als eine vielseitige Technik allgemein für die Zubereitung von vaskulären Grafts mit Nano-faserige Struktur8eingesetzt. Leider führt die relativ kleine Porenstruktur oft zu unzureichend Zelle eindringen in die Electrospun Gefäßprothese, die die nachfolgenden Geweberegeneration begrenzt. Um dieses Problem zu beheben, haben verschiedene Techniken versucht, Erhöhung der Porengröße und insgesamt Porosität, einschließlich das Salz/Polymer Auslaugung9,10, Änderung der Kollektor Apparat, Nachbehandlung durch Laserstrahlung11 , etc.. In der Tat ist die Struktur der Electrospun Transplantate (einschließlich Faserdurchmesser, Porengröße und Porosität) in engem Zusammenhang mit der Verarbeitung Bedingungen12,13. Während Elektrospinnen kann der Faserdurchmesser leicht durch Veränderung der Parameter, wie die Konzentration der Polymerlösung, Durchfluss, Spannung, usw.gesteuert werden. 14 , 15, und daher haben die Porengröße und Porosität entsprechend erhöht worden.
Wir berichteten vor kurzem eine modifizierte PCL Electrospun Transplantat mit makroporösen Struktur (Fasern mit Durchmesser von 5 bis 7 µm und Poren von 30-40 µm). In Vivo Implantation durch den Ersatz der bauchschlagader Ratte zeigten hohe Rate der Durchgängigkeit, sowie gute Endothelialization und glatten Muskulatur Regeneration bei 3 Monate nach der Operation16. Noch wichtiger ist, konnte keine negativen Gewebe Umbau einschließlich Verkalkung und Zelle Regression auch nach einem Jahr der Implantation beobachtet werden.

<table><tbody><tr><td>Poly(&amp;epsilon;-caprolactone) (PCL) pellets (M&lt;sub&gt;n&lt;/sub&gt;=80,000)</td><td>Sigma</td><td>704067</td><td></td></tr><tr><td>Methanol</td><td>Tianjin Chemical Reagent Company</td><td>1060</td><td></td></tr><tr><td>Alcohol</td><td>Tianjin Chemical Reagent Company</td><td>1083</td><td></td></tr><tr><td>Chloroform</td><td>Tianjin Chemical Reagent Company</td><td>A1007</td><td></td></tr><tr><td>Sucrose</td><td>Tianjin Fengchuan Company</td><td>2296</td><td></td></tr><tr><td>Triton X-100</td><td>Alfa Aesar</td><td>A16046</td><td></td></tr><tr><td>Sprague Dawley rats</td><td>Laboratory Animal Center of the Academy of Military Medical Sciences</td><td></td><td></td></tr><tr><td>Normal saline</td><td>Hebei Tiancheng Pharmaceutical company</td><td></td><td></td></tr><tr><td>Chloral hydrate</td><td>Tianjin Ruijinte chemical company</td><td>2223</td><td></td></tr><tr><td>Heparin sodium Injection</td><td>Tianjin Biochem Pharmaceutical company</td><td></td><td></td></tr><tr><td>Gentamycin Sulfate Injection</td><td>Jiangsu Lianshui Pharmaceutical company</td><td></td><td></td></tr><tr><td>Mouse anti-&amp;alpha;-SMA primary antibody</td><td>Abcam</td><td>ab7817</td><td></td></tr><tr><td>Mouse anti-smooth MYH primary antibody</td><td>Abcam</td><td>ab683</td><td></td></tr><tr><td>Rabbit polyclonal anti-rat elastin antibody</td><td>Abcam</td><td>ab23748</td><td></td></tr><tr><td>Rabbit anti-von Willebrand factor primary antibody</td><td>Abcam</td><td>ab6994</td><td></td></tr><tr><td>Goat anti-mouse IgG (Alexa Fluor 488)</td><td>Invitrogen</td><td>ab150117</td><td></td></tr><tr><td>Goat anti-rabbit IgG (Alexa Fluor 488)</td><td>Invitrogen</td><td>ab150077</td><td></td></tr><tr><td>5% normal goat serum</td><td>Zhongshan Golden bridge</td><td>ZLI9022</td><td></td></tr><tr><td>Hematoxylin and eosin (H&amp;amp;E)</td><td>Beijing leagene biotech</td><td>DH0006</td><td></td></tr><tr><td>Masson&#039;s trichrome</td><td>Beijing leagene biotech</td><td>DC0032</td><td></td></tr><tr><td>Verhoeff-van Gieson (VVG)</td><td>Beijing leagene biotech</td><td>DC0059</td><td></td></tr><tr><td>Von Kossa</td><td>Beijing leagene biotech</td><td>DS0003</td><td></td></tr><tr><td>Surgical sutures needles with thread,3-0 silk</td><td>Shanghai Jinhuan medical supplies company</td><td>G3002b</td><td></td></tr><tr><td>Surgical sutures needles with thread,9-0 silk</td><td>Shanghai Jinhuan medical supplies company</td><td>H901</td><td></td></tr></tbody></table>

implantation of electrospun vascular grafts with optimized structure in a rat model

Hier präsentieren wir ein Protokoll, um makroporöse PCL Gefäßprothese zu fabrizieren und beschreiben eine Auswertung Protokoll mithilfe von einem Rattenmodell der bauchschlagader Ersatz. Die Electrospun vascular Grafts besitzen oft relativ kleine Poren, die Zelle eindringen in die Transplantate zu begrenzen und behindert die Regeneration und Remodellierung der Neo-Arterien. In dieser Studie wurden PCL vascular Grafts mit dickeren Fasern (5 – 6 µm) und größere Poren (~ 30 µm) mit einer modifizierten Verarbeitungstechnik hergestellt. Das Langzeitverhalten des Transplantats wurde durch die Implantation in einem Rattenmodell Bauchaorta bewertet. Ultraschall-Analyse zeigte, dass die Transplantate patent ohne Aneurysma oder Stenose auch nach 12 Monaten der Implantation auftreten blieb. Makroporösen Struktur verbessert die Zelle Einwachsen und so gefördert Gewebe regeneriert nach 3 Monaten. Noch wichtiger ist, gab es keine Anzeichen von nachteiligen Umbau, z. B. Verkalkungen innerhalb der Transplantat Wand nach 12 Monaten. Electrospun PCL vascular Grafts mit modifizierten makroporösen Verarbeitung halten Sie daher, mögliche eine Arterie Ersatz für langfristige Implantation.

Die PCL-Transplantate wurden auf 3 Monate und 12 Monate postoperativ explantiert und analysiert durch histologische Standardtechniken für Hämatoxylin und Eosin (H & E), Masson trichrome, Verhoeff-van Gieson (VVG), Von Kossa und Immunfluoreszenz-Färbung für α-SMA, MYH, vWF und Elastin. Die histologische Bilder wurden mit einem aufrechten Mikroskop und die Immunfluoreszenz-Bilder wurden mit einem Fluoreszenzpräparate Mikroskop.
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Watch this Scientific Journal Video about Implantation of Electrospun Vascular Grafts with Optimized Structure in a Rat Model at JoVE.com

Implantation of Electrospun Vascular Grafts with Optimized Structure in a Rat Model

Implantation von Electrospun Vascular Grafts mit optimierter Struktur in einem Rattenmodell

Hier präsentieren wir Ihnen eine geänderte Elektrospinnen Methode PCL vascular Grafts mit dicken Fasern und große Poren zu fabrizieren, und beschreiben ein Protokoll, um die in Vivo -Leistung in einem Rattenmodell der bauchschlagader Ersatz zu bewerten.

Here, we present a protocol to fabricate macroporous PCL vascular graft and describe an evaluation protocol by using a rat model of abdominal aorta ...

implantation-electrospun-vascular-grafts-with-optimized-structure-rat

Universidad de Cartagena UDEC

Research

JoVE Journal

Biology

7.9K Aufrufe.  Nankai University. Hier präsentieren wir Ihnen eine geänderte Elektrospinnen Methode PCL vascular Grafts mit dicken Fasern und große Poren zu fabrizieren, und beschreiben ein Protokoll, um die in Vivo -Leistung in einem Rattenmodell der bauchschlagader Ersatz zu bewerten.

Serie: Implantation of Electrospun Vascular Grafts with Optimized Structure in a Rat Model

Training a Sophisticated Microsurgical Technique: Interposition of External Jugular Vein Graft in the Common Carotid Artery in Rats

Neointimal hyperplasia is one the primary causes of stenosis in arterialized veins that are of great importance in arterial coronary bypass surgery, in peripheral arterial bypass surgery as well as in arteriovenous fistulas.1-5 The experimental procedure of vein graft interposition in the common carotid artery by using the cuff-technique has been applied in several research projects to examine the aetiology of neointimal hyperplasia and therapeutic options to address it. 6-8 The cuff prevents vessel anastomotic remodeling and induces turbulence within the graft and thereby the development of neointimal hyperplasia.
Using the superior caval vein graft is an established small-animal model for venous arterialization experiment.9-11 This current protocol refers to an established jugular vein graft interposition technique first described by Zou et al., 9 as well as others.12-14 Nevertheless, these cited small animal protocols are complicated.
To simplify the procedure and to minimize the number of experimental animals needed, a detailed operation protocol by video training is presented. This video should help the novice surgeon to learn both the cuff-technique and the vein graft interposition. Hereby, the right external jugular vein was grafted in cuff-technique in the common carotid artery of 21 female Sprague Dawley rats categorized in three equal groups that were sacrificed on day 21, 42 and 84, respectively. Notably, no donor animals were needed, because auto-transplantations were performed. The survival rate was 100 % at the time point of sacrifice. In addition, the graft patency rate was 60 % for the first 10 operated animals and 82 % for the remaining 11 animals. The blood flow at the time of sacrifice was 8&plusmn;3 ml/min. In conclusion, this surgical protocol considerably simplifies, optimizes and standardizes this complicated procedure. It gives novice surgeons easy, step-by-step instruction, explaining possible pitfalls, thereby helping them to gain expertise fast and avoid useless sacrifice of experimental animals.

Neointimal hyperplasia is the primary cause of stenosis in arterialized veins. We propose a new protocol whereby the right external jugular vein is grafted using the cuff technique in the common carotid artery of Sprague Dawley rats. The survival rate was 100 % at the time point of sacrifice.

Trainieren eines Sophisticated mikrochirurgische Technik: Interposition der Vena jugularis externa Graft in der Arteria carotis communis bei Ratten

Neointimal hyperplasia is one the primary causes of stenosis in arterialized veins that are of great importance in arterial coronary bypass surgery, in ...

Forschung

Medizin

Implantation of Engineered Tissue in the Rat Heart

Rodent surgery is often an important component in assessing the utility of engineered tissues. A wide variety of surgical procedures can be performed in common laboratory rats or mice and these quite frequently serve as an intermediate step between bench-top experiments and large animal testing or human trials. Given that rodents provide an established, cost-effective, and physiologically-relevant model system in which to test novel combinations of scaffolding materials and cells, they are particularly well-suited for cardiovascular tissue engineering studies. Presently, we describe an open-heart surgical procedure to implant engineered tissue containing myogenic progenitor cells in the atrioventricular (AV) groove of a rat heart. These implants are intended to create an electrical conduit between the right atrium and right ventricle with the ultimate goal of providing an alternative treatment to conventional pacemaker implantation in pediatric patients with complete heart block[1]. The engineered tissue is implanted in the AV-groove by means of a thoracotomy. For our purposes, Lewis rats are anesthetized and invasively ventilated to maintain positive airway pressure during the sterile surgical procedure. The approach to the heart is performed by a right thoracotomy through an antero-lateral incision at the 5th intercostal space. The tissue construct is fixed in the AV groove using a single 7-0 Prolene suture and positioned between the right ventricle and atrium at the ventral portion of the heart. The epicardium is partially removed to allow direct contact between the recipient myocardial cells and those contained in the engineered tissue. Following implantation, the chest wall is closed in layers, any pneumothorax is evacuated, and the animal is extubated and treated with analgesic.

Here, we describe a cardiac surgical procedure to implant engineered tissue in the atrioventricular (AV)-groove of an adult Lewis rat.

Die Implantation von Engineered Tissue in der Ratte Herz

Rodent surgery is often an important component in assessing the utility of engineered tissues. A wide variety of surgical procedures can be performed in ...

Biologie

Surgical Technique for the Implantation of Tissue Engineered Vascular Grafts and Subsequent In Vivo Monitoring

The development of Tissue Engineered Vessels (TEVs) is advanced by the ability to routinely and effectively implant TEVs (4-5 mm in diameter) into a large animal model. A step by-step protocol for inter-positional placement of the TEV and real-time digital assessment of the TEV and native carotid arteries is described here. In vivo monitoring is made possible by the implantation of flow probes, catheters and ultrasonic crystals (capable of recording dynamic diameter changes of implanted TEVs and native carotid arteries) at the time of surgery. Once implanted, researchers can calculate arterial blood flow patterns, invasive blood pressure and artery diameter yielding parameters such as pulse wave velocity, augmentation index, pulse pressures and compliance. Data acquisition is accomplished using a single computer program for analysis throughout the duration of the experiment. Such invaluable data provides insight into TEV matrix remodeling, its resemblance to native/sham controls and overall TEV performance in vivo.

Surgical Technique for the Implantation of Tissue Engineered Vascular Grafts and Subsequent In Vivo Monitoring

A step-by-step protocol for the inter-positional placement of Tissue Engineered Vessels (TEVs) into the carotid artery of a sheep using end-to-end anastomosis and real-time digital assessment in vivo until animal sacrifice.

Operationstechnik zur Implantation von Tissue Engineered Gefäßprothesen und Folge<em&gt; In-vivo-</em&gt; Überwachung

The development of Tissue Engineered Vessels (TEVs) is advanced by the ability to routinely and effectively implant TEVs (4-5 mm in diameter) into a large ...

Biotechnik

Generation and Grafting of Tissue-engineered Vessels in a Mouse Model

The construction of vascular conduits is a fundamental strategy for surgical repair of damaged and injured vessels resulting from cardiovascular diseases. The current protocol presents an efficient and reproducible strategy in which functional tissue engineered vessel grafts can be generated using partially induced pluripotent stem cell (PiPSC) from human fibroblasts. We designed a decellularized vessel scaffold bioreactor, which closely mimics the matrix protein structure and blood flow that exists within a native vessel, for seeding of PiPSC-endothelial cells or smooth muscle cells prior to grafting into mice. This approach was demonstrated to be advantageous because immune-deficient mice engrafted with the PiPSC-derived grafts presented with markedly increased survival rate 3 weeks after surgery. This protocol represents a valuable tool for regenerative medicine, tissue engineering and potentially patient-specific cell-therapy in the near future.

Here, we present a protocol to generate tissue engineered vessel grafts that are functional for grafting into mice by double seeding partially induced pluripotent stem cell (PiPSC) - derived smooth muscle cells and PiPSC - derived endothelial cells on a decellularized vessel scaffold bioreactor.

Generierung und Pfropfen von Tissue Engineering Gefäße in einem Maus-Modell

The construction of vascular conduits is a fundamental strategy for surgical repair of damaged and injured vessels resulting from cardiovascular diseases. ...

Athymic Rat Model for Evaluation of Engineered Anterior Cruciate Ligament Grafts

Anterior cruciate ligament (ACL) rupture is a common ligamentous injury that often requires surgery because the ACL does not heal well without intervention. Current treatment strategies include ligament reconstruction with either autograft or allograft, which each have their associated limitations. Thus, there is interest in designing a tissue-engineered graft for use in ACL reconstruction. We describe the fabrication of an electrospun polymer graft for use in ACL tissue engineering. This polycaprolactone graft is biocompatible, biodegradable, porous, and is comprised of aligned fibers. Because an animal model is necessary to evaluate such a graft, this paper describes an intra-articular athymic rat model of ACL reconstruction that can be used to evaluate engineered grafts, including those seeded with xenogeneic cells. Representative histology and biomechanical testing results at 16 weeks postoperatively are presented, with grafts tested immediately post-implantation and contralateral native ACLs serving as controls. The present study provides a reproducible animal model with which to evaluate tissue engineered ACL grafts, and demonstrates the potential of a regenerative medicine approach to treatment of ACL rupture.

Animal models are important tools for the evaluation of tissue-engineered grafts. This paper presents the protocol for preparing an electrospun biodegradable polymer graft for use in anterior cruciate ligament tissue engineering, as well as a surgical protocol for implantation in a rat model.

Athymischen Rattenmodell für die Bewertung von Engineered vorderen Kreuzbandes Grafts

Anterior cruciate ligament (ACL) rupture is a common ligamentous injury that often requires surgery because the ACL does not heal well without ...

Implantation of Inferior Vena Cava Interposition Graft in Mouse Model

Biodegradable scaffolds seeded with bone marrow mononuclear cells (BMCs) are often used for reconstructive surgery to treat congenital cardiac anomalies. The long-term clinical results showed excellent patency rates, however, with significant incidence of stenosis. To investigate the cellular and molecular mechanisms of vascular neotissue formation and prevent stenosis development in tissue engineered vascular grafts (TEVGs), we developed a mouse model of the graft with approximately 1 mm internal diameter. First, the TEVGs were assembled from biodegradable tubular scaffolds fabricated from a polyglycolic acid nonwoven felt mesh coated with &#949;-caprolactone and L-lactide copolymer. The scaffolds were then placed in a lyophilizer, vacuumed for 24 hr, and stored in a desiccator until cell seeding. Second, bone marrow was collected from donor mice and mononuclear cells were isolated by density gradient centrifugation. Third, approximately one million cells were seeded on a scaffold and incubated O/N. Finally, the seeded scaffolds were then implanted as infrarenal vena cava interposition grafts in C57BL/6 mice. The implanted grafts demonstrated excellent patency (&#62;90%) without evidence of thromboembolic complications or aneurysmal formation. This murine model will aid us in understanding and quantifying the cellular and molecular mechanisms of neotissue formation in the TEVG.

To improve our knowledge of cellular and molecular neotissue formation, a murine model of the TEVG was recently developed. The grafts were implanted as infrarenal vena cava interposition grafts in C57BL/6 mice. This model achieves similar results to those achieved in our clinical investigation, but over a far shortened time-course.

Die Implantation von Vena Cava Interposition Graft in Maus-Modell

Biodegradable scaffolds seeded with bone marrow mononuclear cells (BMCs) are often used for reconstructive surgery to treat congenital cardiac anomalies. ...

The Arteriovenous (AV) Loop in a Small Animal Model to Study Angiogenesis and Vascularized Tissue Engineering

A functional blood vessel network is a prerequisite for the survival and growth of almost all tissues and organs in the human body. Moreover, in pathological situations such as cancer, vascularization plays a leading role in disease progression. Consequently, there is a strong need for a standardized and well-characterized in vivo model in order to elucidate the mechanisms of neovascularization and develop different vascularization approaches for tissue engineering and regenerative medicine.
We describe a microsurgical approach for a small animal model for induction of a vascular axis consisting of a vein and artery that are anastomosed to an arteriovenous (AV) loop. The AV loop is transferred to an enclosed implantation chamber to create an isolated microenvironment in vivo, which is connected to the living organism only by means of the vascular axis. Using 3D imaging (MRI, micro-CT) and immunohistology, the growing vasculature can be visualized over time. By implanting different cells, growth factors and matrices, their function in blood vessel network formation can be analyzed without any disturbing influences from the surroundings in a well controllable environment. 
In addition to angiogenesis and antiangiogenesis studies, the AV loop model is also perfectly suited for engineering vascularized tissues. After a certain prevascularization time, the generated tissues can be transplanted into the defect site and microsurgically connected to the local vessels, thereby ensuring immediate blood supply and integration of the engineered tissue. By varying the matrices, cells, growth factors and chamber architecture, it is possible to generate various tissues, which can then be tailored to the individual patient's needs.

The Arteriovenous AV Loop in a Small Animal Model to Study Angiogenesis and Vascularized Tissue Engineering

We describe a microsurgical approach for the generation of an arteriovenous (AV) loop as a model for analyzing vascularization in vivo in an isolated and well-characterized environment. This model is not only useful for the investigation of angiogenesis, but is also optimally suited for engineering axially vascularized and transplantable tissues.

Die arteriovenöse (AV) Loop in einem Kleintiermodell zur Untersuchung Angiogenesis und Vaskularisierte Tissue Engineering

A functional blood vessel network is a prerequisite for the survival and growth of almost all tissues and organs in the human body. Moreover, in ...

Tissue-Engineered Graft for Circumferential Esophageal Reconstruction in Rats

The use of biocompatible materials for circumferential esophageal reconstruction is a technically challenging task in rats and requires an optimal implant technique with nutritional support. Recently, there have been many attempts at esophageal tissue engineering, but the success rate has been limited due to difficulty in early epithelization in the special environment of peristalsis. Here, we developed an artificial esophagus that can improve the regeneration of the esophageal mucosa and muscle layers through a two-layered tubular scaffold, a mesenchymal stem cell-based bioreactor system, and a bypass feeding technique with modified gastrostomy. The scaffold is made of polyurethane (PU) nanofibers in a cylindrical shape with a three-dimensional (3D) printed polycaprolactone strand wrapped around the outer wall. Prior to transplantation, human-derived mesenchymal stem cells were seeded into the lumen of the scaffold, and bioreactor cultivation was performed to enhance cellular reactivity. We improved the graft survival rate by applying surgical anastomosis and covering the implanted prosthesis with a thyroid gland flap, followed by temporary nonoral gastrostomy feeding. These grafts were able to recapitulate the findings of initial epithelialization and muscle regeneration around the implanted sites, as demonstrated by histological analysis. In addition, increased elastin fibers and neovascularization were observed in the periphery of the graft. Therefore, this model presents a potential new technique for circumferential esophageal reconstruction.

Esophageal reconstruction is a challenging procedure, and development of a tissue-engineered esophagus that enables regeneration of esophageal mucosa and muscle and that can be implanted as an artificial graft is necessary. Here, we present our protocol to generate an artificial esophagus, including scaffold manufacturing, bioreactor cultivation, and various surgical techniques.

The use of biocompatible materials for circumferential esophageal reconstruction is a technically challenging task in rats and requires an optimal implant ...

Vein Interposition Model: A Suitable Model to Study Bypass Graft Patency

Bypass grafting is an established treatment method for coronary artery disease. Graft patency continues to be the Achilles heel of saphenous vein grafts. Research models for bypass graft failure are essential for a better understanding of pathobiological and pathophysiological processes during graft patency loss. Large animal models, such as pigs or sheep, resemble human anatomical structures but require special facilities and equipment. This video describes a rat vein interposition model to investigate vein graft patency loss. Rats are inexpensive and easy to handle. Compared to mouse models, the convenient size of rats permits better operability and enables a sufficient amount of material to be obtained for further diverse analysis. In brief, the inferior epigastric vein of a donor rat is harvested and used to replace a segment of the femoral artery. Anastomosis is conducted via single stitches and sealed with fibrin glue. Graft patency can be monitored non-invasively using duplex sonography. Myointimal hyperplasia, which is the main cause for graft patency loss, develops progressively over time and can be calculated from histological cross sections.

This video demonstrates a model to study the development of myointimal hyperplasia after venous interposition surgery in rats.

Vein Interposition Modell: ein geeignetes Modell zur Untersuchung Bypass Graft Durchgängigkeit

Bypass grafting is an established treatment method for coronary artery disease. Graft patency continues to be the Achilles heel of saphenous vein grafts. ...

Implantation of Tissue-Engineered Vascular Graft in Mouse Carotid Artery via Cuff Technique

The development of small-diameter vascular grafts has been a global endeavor, with numerous research groups contributing to this field. Animal experimentation plays a pivotal role in assessing the efficacy and safety of vascular grafts, particularly in the absence of clinical applications. Compared to alternative animal models, the mouse implantation model offers several advantages, including a well-defined genetic background, a mature method for disease model construction, and a straightforward surgical procedure. Based on these advantages, the present study devised a simple cuff technique for the implantation of tissue-engineered vascular grafts in the mouse carotid artery. This technique began with the fabrication of polycaprolactone (PCL) small-diameter vascular grafts via electrostatic spinning, followed by the seeding of macrophages onto the grafts through perfusion adsorption. Subsequently,&#160;the cellularized tissue-engineered vascular grafts were transplanted into the mouse carotid artery using the cuff technique to evaluate patency and regenerative capability. After 30 days of in vivo implantation, vascular patency was found to be satisfactory, with evidence of neo-tissue regeneration and the formation of an endothelial layer within the lumen of the grafts. All data were analyzed using statistical and graphing software. This study successfully established a mouse carotid artery implantation model that can be used to explore the cellular sources of vascular regeneration and the mechanisms of action of active substances. Furthermore, it provides theoretical support for the development of novel small-diameter vascular grafts.

Here, a protocol is presented for the implantation of a tissue-engineered vascular graft into the mouse carotid artery using the cuff technique, providing a suitable animal model for investigating vascular tissue regeneration mechanisms.

Implantation von Electrospun Vascular Grafts mit optimierter Struktur in einem Rattenmodell

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