Gli autori desiderano ringraziare Leica Microsystems per i loro preziosi consigli su immagini sezioni titanio e Gemini Bio-Prodotti per la fornitura del siero suina utilizzati in questo studio. Ci piace anche ringraziare i NIH per il loro sostegno attraverso Grant &quot;rivestimento autologo EPC per migliorare la biocompatibilità dei dispositivi di assistenza circolatoria&quot;, RC1HL099863-01. Inoltre, siamo grati per il supporto della National Science Foundation Graduate Research Fellowship di Alexandra Jantzen. Ci piace anche ringraziare George rapida, Mike Lowe e Ianthia Parker per assistere con molti aspetti della procedura chirurgica e la gestione dei nostri animali di ricerca. Steven Owen è stato prezioso per la lavorazione di pezzi molti dei nostri dispositivi semina e taglio di tubi in titanio.

<ol>
	<li>Achneck, H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathophysiology+of+bleeding+and+clotting+in+the+cardiac+surgery+patient:+from+vascular+endothelium+to+circulatory+assist+device+surface.">Pathophysiology of bleeding and clotting in the cardiac surgery patient: from vascular endothelium to circulatory assist device surface.</a> Circulation. 122, 2068-2077 (2010).</li><li>Achneck, H. E., Sileshi, B., Lawson, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+of+the+biology+of+bleeding+and+clotting+in+the+surgical+patient.">Review of the biology of bleeding and clotting in the surgical patient.</a> Vascular. 16, 6-13 (2008).</li><li>Arvidsson, S., Askendal, A., Tengvall, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blood+plasma+contact+activation+on+silicon,+titanium+and+aluminium.">Blood plasma contact activation on silicon, titanium and aluminium.</a> Biomaterials. 28, 1346-1354 (2007).</li><li>Achneck, H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+biocompatibility+of+titanium+cardiovascular+devices+seeded+with+autologous+blood-derived+endothelial+progenitor+cells:+EPC-seeded+antithrombotic+Ti+Implants.">The biocompatibility of titanium cardiovascular devices seeded with autologous blood-derived endothelial progenitor cells: EPC-seeded antithrombotic Ti Implants.</a> Biomaterials. 32, 10-18 (2011).</li><li>Kang, C., Bonneau, M., Brouland, J. P., Bal dit Sollier, C., Drouet, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+pig+models+of+venous+thrombosis+mimicking+human+disease.">In vivo pig models of venous thrombosis mimicking human disease.</a> Thromb Haemost. 89, 256-263 (2003).</li><li>Ueberrueck, T. <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+the+ovine+and+porcine+animal+models+for+biocompatibility+testing+of+vascular+prostheses.">Comparison of the ovine and porcine animal models for biocompatibility testing of vascular prostheses.</a> J Surg Res. 124, 305-311 (2005).</li><li>Velik-Salchner, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Normal+values+for+thrombelastography+(ROTEM)+and+selected+coagulation+parameters+in+porcine+blood.">Normal values for thrombelastography (ROTEM) and selected coagulation parameters in porcine blood.</a> Thromb Res. 117, 597-602 (2006).</li><li>Yoder, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Redefining+endothelial+progenitor+cells+via+clonal+analysis+and+hematopoietic+stem/progenitor+cell+principals.">Redefining endothelial progenitor cells via clonal analysis and hematopoietic stem/progenitor cell principals.</a> Blood. 109, 1801-1809 (2007).</li><li>Achneck, H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> American Heart Association Scientific Sessions, Abstract Oral Sessions, Medical Aspects End Stage Heart Failure: Transplantation and Device Therapies. , (2010).</li><li>Achneck, H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regenerating+titanium+ventricular+assist+device+surfaces+after+gold/palladium+coating+for+scanning+electron+microscopy.">Regenerating titanium ventricular assist device surfaces after gold/palladium coating for scanning electron microscopy.</a> Microsc Res Tech. 73, 71-76 (2010).</li><li>Ford, J. W., Welling, T. H., Stanley, J. C., Messina, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PKH26+and+125I-PKH95:+characterization+and+efficacy+as+labels+for+in+vitro+and+in+vivo+endothelial+cell+localization+and+tracking.">PKH26 and 125I-PKH95: characterization and efficacy as labels for in vitro and in vivo endothelial cell localization and tracking.</a> J Surg Res. 62, 23-28 (1996).</li></ol>

Nessun conflitto di interessi dichiarati.

Il metodo di cellule semina tubi Ti presentato qui permette ai medici e agli scienziati di endothelialize rapidamente e in modo uniforme il sangue a contatto superfici di dispositivi impiantabili. Dal momento che abbiamo isolare ed espandere EPC da campioni di sangue periferico, nessuna procedura di grandi invasiva è necessaria per sfruttare queste cellule. Inoltre, l&#39;EPC sono autologhe, quindi, il rischio di reazione immunitaria alla cella testa di serie impianto viene eliminato. I principi dimostrato nel suo protocollo può essere utilizzato non solo per i tubi di titanio, ma per molti altri biomateriali, che vengono utilizzate nella medicina cardiovascolare. Passaggi critici in questo protocollo sono la pulizia meticolosa dei tubi Ti, come abbiamo scoperto che ogni pellicola aderente di contaminante cellule aderenza compromessi. Inoltre, una velocità di rotazione lenta (inversamente proporzionale al diametro del tubo) è essenziale durante il processo di semina, in modo che lentamente EPC possono stabilirsi e aderire alla superficie del tubo Ti è in movimento. Il nostro metodo di semina immediatamente prima dell&#39;impianto evitando impraticabile ex tempi cultura vivo; cellule aderire individualmente e in seguito forma un foglio confluenti in vivo, evitando la possibilità di embolizzazione come un foglio subito dopo il ristabilimento del flusso. I nostri studi precedenti mostrano che una volta che l&#39;EPC sono cresciuti a un livello confluenti, fanno un matrice extracellulare a cui aderire, in aggiunta al minimo ogni possibile mutare di un foglio endoteliale. Anche se la possibilità di distacco embolico non può essere completamente escluso, sembra essere molteplici rischio inferiore trombosi della superficie intero dispositivo, il problema che questa terapia è stato progettato per prevenire. Il nostro approccio di impianto nel taglio basso, l&#39;ambiente protrombotici della vena cava inferiore utilizza uno dei modelli più affidabili grande animale per la ricerca di compatibilità del sangue e trombosi dei dispositivi di 5,6. Si noti che tutti la cura degli animali e la sperimentazione è stata condotta in conformità con l&#39;Istituto Nazionale della Salute Linee guida per la cura e l&#39;uso di animali da laboratorio e solo dopo l&#39;approvazione dei prodotti per animali Duke University e del Comitato Istituzionale Usa. Al fine di utilizzare con successo questo metodo per testare l&#39;impianto biomateriali e dispositivi, è importante skeletonize pazientemente il segmento IVC e legare tutte le navi ramo venoso in preparazione per l&#39;inserimento dispositivo, tale che nessun sanguinamento intorno al dispositivo originario di un &#39;falso lume&#39;. Un altro passo fondamentale è l&#39;aggiunta di DPBS nel lume dispositivo in modo che le cellule sulla superficie interna del tubo rimanere umido durante la chiusura del veinotomy e prima di riperfusione è iniziata. Se il dispositivo non può essere trovato nella posizione in cui è stato impiantato, può avere migrato &#39;a monte&#39; nella IVC. Questo può essere evitato mettendo una sutura (4-O Prolene) attraverso la parete venosa e attraverso un 2-3 mm di sezione del tubo in PVC in modo che il tubo sia saldamente ancorata nella sua posizione attuale. Qualora il ricercatore hanno difficoltà a trovare le cellule fluorescenza pre-etichettati mostrato nella Figura 8, dopo espianto in un tubo di brevetto in caso contrario, è probabile che le cellule hanno staccata come un foglio coerente. Questo può essere impedito da dissezione molto delicato della vena circostante e smontaggio delle 3 sezioni del tubo Ti, dopo aver fissato la vena insieme con il tubo. La nostra tecnologia fornisce proof-of-concept per prevenire la trombosi cardiovascolare dispositivo attraverso EPC-semina. Questa tecnologia può essere utilizzata per lo sviluppo di &#39;biogene&#39; impianti fiancheggiata da cellule dei pazienti &#39;progenitrici endoteliali. Lo studio di fattibilità nel nostro modello animale della specie suina prevede i primi passi verso la traduzione di questa &#39;medicina personalizzata&#39; nella pratica clinica.

<table border="1"><tbody><tr><td> Reagente </td><td> Nome Azienda </td><td> Numero di catalogo </td><td> Commenti </td></tr><tr><td> Acepromazina </td><td> Boehringer-Ingelheim </td><td> BIC670025 </td><td> NAC # 10280002 </td></tr><tr><td> Alconox Pulitore di precisione Powered </td><td> Alconox </td><td> 1104 </td><td></td></tr><tr><td> Balfour Retrattore chirurgica </td><td> Adler </td><td> N / A </td><td></td></tr><tr><td> Baytril </td><td> Bayer </td><td> APVMA 46028/0705 </td><td></td></tr><tr><td> Farfalla ago (19G) </td><td> Terumo </td><td> SV19CLK </td><td></td></tr><tr><td> Clorexidina </td><td> 3M </td><td> 9200 </td><td></td></tr><tr><td> Morsetti (45 gradi) </td><td> Aesculap </td><td> FC339T </td><td></td></tr><tr><td> DPBS (-/-) </td><td> Gibco </td><td> 14190-144 </td><td></td></tr><tr><td> DPBS (+/+) </td><td> Gibco </td><td> 14040-133 </td><td></td></tr><tr><td> DuraPrep </td><td> 3M </td><td> 8635 </td><td></td></tr><tr><td> EBM-2 Media </td><td> Lonza </td><td> CC-3156 </td><td> Base per la crescita di medio siero libero e pieno </td></tr><tr><td> EGM-2 SingleQuots </td><td> Lonza </td><td> CC-3162 </td><td> Utilizzato con EBM-2 sia per la crescita media del siero libero e pieno </td></tr><tr><td> Strumento elettrocauterizzazione </td><td> Valleylab </td><td> SurgII-20 </td><td></td></tr><tr><td> Panno smeriglio </td><td> 3M </td><td> 60-0700-0425-8 </td><td> Grana 240 </td></tr><tr><td> Euthasol Eutanasia Soluzione </td><td> Virback Animal Health </td><td></td><td> ANADA #: 200-071 </td></tr><tr><td> Fentanil Patch </td><td> Actavis </td><td></td><td> NDC # 67767-120-18 </td></tr><tr><td> Flunixin </td><td> Schering-Plough </td><td></td><td> NAC #: 10470183 </td></tr><tr><td> Foley Catheter (16F) </td><td> Vate </td><td> 730116 </td><td></td></tr><tr><td> HBSS </td><td> Sigma </td><td> H8264-500ML </td><td></td></tr><tr><td> Pistola di calore </td><td> Milwaukee </td><td> 8988-20 </td><td></td></tr><tr><td> Eparina </td><td></td><td></td><td> NDC #: 25021 </td></tr><tr><td> HISTOPAQUE-1077 </td><td> Sigma </td><td> H8889-500ML </td><td></td></tr><tr><td> Intubazione del tubo </td><td> Mallinckrodt </td><td> 86113 </td><td></td></tr><tr><td> Isoflurano </td><td> MWI, Meridian </td><td></td><td> NDC # 13985-030 </td></tr><tr><td> IV catetere (18G) </td><td> Becton Dickinson- </td><td> 381547 </td><td></td></tr><tr><td> Ketamina </td><td> Fort Dodge </td><td></td><td> NDC # 0856-2013 </td></tr><tr><td> Livello </td><td> Swanson </td><td> LLA001 </td><td></td></tr><tr><td> Luer-Lock cappuccio </td><td> CML di alimentazione </td><td> 909-001 </td><td></td></tr><tr><td> Marcaine </td><td> Hospira </td><td></td><td> NDC #: 0409-1560-10 </td></tr><tr><td> Metzenbaum Forbici </td><td> Adler </td><td> N / A </td><td></td></tr><tr><td> Micro-introduttore (5F) </td><td> Galt </td><td> KIT 002-01 </td><td></td></tr><tr><td> Pinza Mosquito </td><td> Adler </td><td> N / A </td><td></td></tr><tr><td> Motore </td><td> Herbach e Rademan </td><td> H1-08 </td><td></td></tr><tr><td> Ossimorfone </td><td> Endo Labs </td><td></td><td> NDC: 63481-624-10 </td></tr><tr><td> PKH26 Dye Kit </td><td> Sigma </td><td> PKH26GL-1KT </td><td></td></tr><tr><td> Suini Siero </td><td> Gemini Bio-Prodotti </td><td> 100-115 </td><td> Concentrazione del 2% nel medio piena crescita </td></tr><tr><td> Potts Forbici </td><td> Adler </td><td> N / A </td><td></td></tr><tr><td> Preciso Vista pelle pinzatrice </td><td> 3M </td><td> 3998 </td><td></td></tr><tr><td> Tubi in PVC </td><td> McMaster-Carr/Insultab </td><td> 7132K117 </td><td> ampliato ID 15,88 millimetri, recuperato ID 7,95 millimetri </td></tr><tr><td> Diritto grandezza media in angolo </td><td> Adler </td><td> N / A </td><td></td></tr><tr><td> Scalpel Blade (# 10-15) </td><td> Vate </td><td> 373910 </td><td></td></tr><tr><td> Tubi in silicone </td><td> McMaster-Carr </td><td> 51735K26 </td><td> 16,64 millimetri OD, 9.52 mm ID </td></tr><tr><td> Siringa (5 cc) </td><td> Becton-Dickinson (BD) </td><td> 309603 </td><td></td></tr><tr><td> Tegaderm </td><td> 3M </td><td> 90001 </td><td></td></tr><tr><td> Rubinetto a tre vie </td><td> Kendall </td><td> 170060 </td><td></td></tr><tr><td> Ti tubo </td><td> Tico titanio </td><td> N / A </td><td> Specificato come ½ &quot;OD, 0,065&quot; muro, 0,370 &quot;ID, 0,1737 £ / ft </td></tr><tr><td> Tripsina </td><td> Lonza </td><td> CC-5012 </td><td></td></tr><tr><td> Tripsina soluzione neutralizzante (TNS) </td><td> Lonza </td><td> CC-5002 </td><td> 0,03% </td></tr><tr><td> Vetropolycin </td><td> Pharmaderm Animal Health </td><td></td><td> NAC #: 12920110 </td></tr><tr><td> Suture Vicryl (3-0) </td><td> Ethicon </td><td> J808T </td><td></td></tr><tr><td> Acqua bagno Sonicator </td><td> Branson </td><td> B200 </td><td></td></tr></tbody></table>

autologous endothelial progenitor cell-seeding technology and biocompatibility testing for cardiovascular devices in large animal model

Dispositivi impiantabili cardiovascolari sono realizzati con materiali artificiali (per esempio in titanio (Ti), politetrafluoroetilene espanso), che comportano il rischio di formazione di tromboembolie 1,2,3. Abbiamo sviluppato un metodo per allineare la superficie interna dei tubi Ti con cellule umane autologhe o suina emoderivati ​​progenitrici endoteliali (EPC) 4. Mediante l&#39;impianto di tubi di titanio contenente uno strato confluente di EPC suina nella vena cava inferiore (IVC) di suini, abbiamo testato la biocompatibilità miglioramento della cellula-superficie seminata in ambiente protrombotico di un modello animale di grandi dimensioni e non modificato rispetto a superfici di metallo nudo 5,6,7 (Figura 1). Questo metodo può essere utilizzato per endothelialize dispositivi in pochi minuti di impianto e testare la loro funzione antitrombotica in vivo. Sangue periferico è stato ottenuto da 50 kg Yorkshire suina e la sua frazione di cellule mononucleate in coltura per isolare EPC 4,8. Ti tubi (9,4 mm ID) sono stati pre-tagliati in tre sezioni 4,5 centimetri longitudinale e riassemblati con una guaina termoretraibile. Un dispositivo di semina è stata costruita, che consente la rotazione lenta dei tubi Ti. Abbiamo eseguito una laparotomia sui maiali e esteriorizzato dell&#39;intestino e della vescica urinaria. Dissezione acuto e schietto è stato utilizzato per skeletonize l&#39;IVC dalla sua biforcazione distale dell&#39;arteria renale destra prossimale. I tubi Ti sono stati poi riempiti con fluorescenza marcata autologo sospensione EPC e ruotato di 10 RPH x 30 minuti per raggiungere uniforme delle cellule di rivestimento 9. Dopo la somministrazione di 100 USP / kg di eparina, entrambe le estremità della IVC e una vena lombare sono stati bloccati. A 4 veinotomy centimetri è stata effettuata e il dispositivo inserito e pieno di PBS. Mentre il veinotomy è stata chiusa con una sutura Prolene 4-0 in esecuzione, un morsetto è stato rimosso a de-air la IVC. Al termine della procedura, la fascia è stata approssimata con 0-PDS (polidiossanone sutura), lo spazio sottocutaneo chiuso con Vicryl 2-0 e la pelle cucito con punti metallici chiusi. Dopo 3 - 21 giorni, i maiali sono stati sottoposti ad eutanasia, il dispositivo espiantato en-blocco e fissi. I tubi Ti sono stati smontati e le superfici interne ripreso con un microscopio a fluorescenza. Abbiamo scoperto che il metallo nudo tubi Ti completamente occluso considerando che la SPE-teste di serie tubi rimasti brevetto. Inoltre, siamo stati in grado di dimostrare uno strato confluente di EPC all&#39;interno del sangue a contatto della superficie. Concludendo, la nostra tecnologia può essere usata per endothelialize tubi Ti pochi minuti di impianto con EPC autologhe per prevenire la trombosi del dispositivo. Il nostro metodo chirurgico consente di testare la biocompatibilità miglioramento di tali dispositivi modificati con minima perdita di sangue ed EPC-seminato distruzione di superficie.

Watch this Scientific Journal Video about Autologous Endothelial Progenitor Cell-Seeding Technology and Biocompatibility Testing For Cardiovascular Devices in Large Animal Model at JoVE.com

Autologous Endothelial Progenitor Cell-Seeding Technology and Biocompatibility Testing For Cardiovascular Devices in Large Animal Model

Un metodo per il titanio semina sangue a contatto con le cellule autologhe biomateriali e biocompatibilità test è descritta. Questo metodo utilizza cellule progenitrici endoteliali e tubi in titanio, teste di serie in pochi minuti di impianto chirurgico nelle cave cavae suina. Questa tecnica è adattabile a molti altri dispositivi biomedici impiantabili.

Autologo di cellule progenitrici endoteliali-Seeding Tecnologie e test di biocompatibilità per dispositivi cardiovascolari in un modello animale di grandi dimensioni

Implantable cardiovascular devices are manufactured from artificial materials (e.g. titanium (Ti), expanded polytetrafluoroethylene), which pose the risk ...

autologous-endothelial-progenitor-cell-seeding-technology

Research

JoVE Journal

Bioengineering

20.3K Views.  Duke University. Un metodo per il titanio semina sangue a contatto con le cellule autologhe biomateriali e biocompatibilità test è descritta. Questo metodo utilizza cellule progenitrici endoteliali e tubi in titanio, teste di serie in pochi minuti di impianto chirurgico nelle cave cavae suina. Questa tecnica è adattabile a molti altri dispositivi biomedici impiantabili.

Video: Autologous Endothelial Progenitor Cell-Seeding Technology and Biocompatibility Testing For Cardiovascular Devices in Large Animal Model

Electric Cell-substrate Impedance Sensing for the Quantification of Endothelial Proliferation, Barrier Function, and Motility

Electric Cell-substrate Impedance Sensing (ECIS) is an in vitro impedance measuring system to quantify the behavior of cells within adherent cell layers. To this end, cells are grown in special culture chambers on top of opposing, circular gold electrodes. A constant small alternating current is applied between the electrodes and the potential across is measured. The insulating properties of the cell membrane create a resistance towards the electrical current flow resulting in an increased electrical potential between the electrodes. Measuring cellular impedance in this manner allows the automated study of cell attachment, growth, morphology, function, and motility. Although the ECIS measurement itself is straightforward and easy to learn, the underlying theory is complex and selection of the right settings and correct analysis and interpretation of the data is not self-evident. Yet, a clear protocol describing the individual steps from the experimental design to preparation, realization, and analysis of the experiment is not available. In this article the basic measurement principle as well as possible applications, experimental considerations, advantages and limitations of the ECIS system are discussed. A guide is provided for the study of cell attachment, spreading and proliferation; quantification of cell behavior in a confluent layer, with regard to barrier function, cell motility, quality of cell-cell and cell-substrate adhesions; and quantification of wound healing and cellular responses to vasoactive stimuli. Representative results are discussed based on human microvascular (MVEC) and human umbilical vein endothelial cells (HUVEC), but are applicable to all adherent growing cells.

This protocol reviews Electric Cell-substrate Impedance Sensing, a method to record and analyze the impedance spectrum of adherent cells for the quantification of cell attachment, proliferation, motility, and cellular responses to pharmacological and toxic stimuli. Detection of endothelial permeability and assessment of cell-cell and cell-substrate contacts are emphasized.

Elettrico Cell-substrato Impedance Sensing per la quantificazione dei Endothelial proliferazione, Barriera funzione e motilità

Electric Cell-substrate Impedance Sensing (ECIS) is an in vitro impedance measuring system to quantify the behavior of cells within adherent cell layers. ...

Ricerca

Bioingegneria

Layer-by-layer Collagen Deposition in Microfluidic Devices for Microtissue Stabilization

Although microfluidics provides exquisite control of the cellular microenvironment, culturing cells within microfluidic devices can be challenging. 3D culture of cells in collagen type I gels helps to stabilize cell morphology and function, which is necessary for creating microfluidic tissue models in microdevices. Translating traditional 3D culture techniques for tissue culture plates to microfluidic devices is often difficult because of the limited channel dimensions. In this method, we describe a technique for modifying native type I collagen to generate polycationic and polyanionic collagen solutions that can be used with layer-by-layer deposition to create ultrathin collagen assemblies on top of cells cultured in microfluidic devices. These thin collagen layers stabilize cell morphology and function, as shown using primary hepatocytes as an example cell, allowing for the long term culture of microtissues in microfluidic devices.

The creation of functional microtissues within microfluidic devices requires the stabilization of cell phenotypes by adapting traditional cell culture techniques to the limited spatial dimensions in microdevices. Modification of collagen allows the layer-by-layer deposition of ultrathin collagen assemblies that can stabilize primary cells, such as hepatocytes, as microfluidic tissue models.

Layer-by-layer collagene Deposizione nel Microfluidic Dispositivi per microtessuto Stabilizzazione

Although microfluidics provides exquisite control of the cellular microenvironment, culturing cells within microfluidic devices can be challenging. 3D ...

Ferromagnetic Bare Metal Stent for Endothelial Cell Capture and Retention

Rapid endothelialization of cardiovascular stents is needed to reduce stent thrombosis and to avoid anti-platelet therapy which can reduce bleeding risk. The feasibility of using magnetic forces to capture and retain endothelial outgrowth cells (EOC) labeled with super paramagnetic iron oxide nanoparticles (SPION) has been shown previously. But this technique requires the development of a mechanically functional stent from a magnetic and biocompatible material followed by in-vitro and in-vivo testing to prove rapid endothelialization. We developed a weakly ferromagnetic stent from 2205 duplex stainless steel using computer aided design (CAD) and its design was further refined using finite element analysis (FEA). The final design of the stent exhibited a principal strain below the fracture limit of the material during mechanical crimping and expansion. One hundred stents were manufactured and a subset of them was used for mechanical testing, retained magnetic field measurements, in-vitro cell capture studies, and in-vivo implantation studies. Ten stents were tested for deployment to verify if they sustained crimping and expansion cycle without failure. Another 10 stents were magnetized using a strong neodymium magnet and their retained magnetic field was measured. The stents showed that the retained magnetism was sufficient to capture SPION-labeled EOC in our in-vitro studies. SPION-labeled EOC capture and retention was verified in large animal models by implanting 1 magnetized stent and 1 non-magnetized control stent in each of 4 pigs. The stented arteries were explanted after 7 days and analyzed histologically. The weakly magnetic stents developed in this study were capable of attracting and retaining SPION-labeled endothelial cells which can promote rapid healing.

Our goals were to design, manufacture and test ferromagnetic stents for endothelial cell capture. Ten stents were tested for fracture and 10 more stents were tested for retained magnetism. Finally, 10 stents were tested in-vitro and 8 more stents were implanted in 4 pigs to show cell capture and retention.

Bare Metal Stent ferromagnetico per Capture cellule endoteliali e conservazione

Rapid endothelialization of cardiovascular stents is needed to reduce stent thrombosis and to avoid anti-platelet therapy which can reduce bleeding risk. ...

Fabrication of Custom Agarose Wells for Cell Seeding and Tissue Ring Self-assembly Using 3D-Printed Molds

Engineered tissues are being used clinically for tissue repair and replacement, and are being developed as tools for drug screening and human disease modeling. Self-assembled tissues offer advantages over scaffold-based tissue engineering, such as enhanced matrix deposition, strength, and function. However, there are few available methods for fabricating 3D tissues without seeding cells on or within a supporting scaffold. Previously, we developed a system for fabricating self-assembled tissue rings by seeding cells into non-adhesive agarose wells. A polydimethylsiloxane (PDMS) negative was first cast in a machined polycarbonate mold, and then agarose was gelled in the PDMS negative to create ring-shaped cell seeding wells. However, the versatility of this approach was limited by the resolution of the tools available for machining the polycarbonate mold. Here, we demonstrate that 3D-printed plastic can be used as an alternative to machined polycarbonate for fabricating PDMS negatives. The 3D-printed mold and revised mold design is simpler to use, inexpensive to produce, and requires significantly less agarose and PDMS per cell seeding well. We have demonstrated that the resulting agarose wells can be used to create self-assembled tissue rings with customized diameters from a variety of different cell types. Rings can then be used for mechanical, functional, and histological analysis, or for fabricating larger and more complex tubular tissues.

This protocol describes a platform for fabricating self-assembled tissue rings in variable sizes using a customized 3D-printed plastic mold. PDMS negatives are cured in the 3D-printed mold; then agarose is cast in the cured PDMS negatives. Cells are seeded into the resulting agarose wells where they aggregate into tissue rings.

Fabbricazione di pozzi di agarosio personalizzato per la semina delle cellule e tessuto anello auto-assemblaggio utilizzando stampi 3D-stampato

Engineered tissues are being used clinically for tissue repair and replacement, and are being developed as tools for drug screening and human disease ...

Electric and Magnetic Field Devices for Stimulation of Biological Tissues

Electric fields (EFs) and magnetic fields (MFs) have been widely used by tissue engineering to improve cell dynamics such as proliferation, migration, differentiation, morphology, and molecular synthesis. However, variables such stimuli strength and stimulation times need to be considered when stimulating either cells, tissues or scaffolds. Given that EFs and MFs vary according to cellular response, it remains unclear how to build devices that generate adequate biophysical stimuli to stimulate biological samples. In fact, there is a lack of evidence regarding the calculation and distribution when biophysical stimuli are applied. This protocol is focused on the design and manufacture of devices to generate EFs and MFs and implementation of a computational methodology to predict biophysical stimuli distribution inside and outside of biological samples. The EF device was composed of two parallel stainless-steel electrodes located at the top and bottom of biological cultures. Electrodes were connected to an oscillator to generate voltages (50, 100, 150 and 200 Vp-p) at 60 kHz. The MF device was composed of a coil, which was energized with a transformer to generate a current (1 A) and voltage (6 V) at 60 Hz. A polymethyl methacrylate support was built to locate the biological cultures in the middle of the coil. The computational simulation elucidated the homogeneous distribution of EFs and MFs inside and outside of biological tissues. This computational model is a promising tool that can modify parameters such as voltages, frequencies, tissue morphologies, well plate types, electrodes and coil size to estimate the EFs and MFs to achieve a cellular response.

This protocol describes the step-by-step process to build both electrical and magnetic stimulators used to stimulate biological tissues. The protocol includes a guideline to simulate computationally electric and magnetic fields and manufacture of stimulator devices.

Dispositivi elettrici e a campo magnetico per la stimolazione dei tessuti biologici

Electric fields (EFs) and magnetic fields (MFs) have been widely used by tissue engineering to improve cell dynamics such as proliferation, migration, ...

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.

Un grande modello animale per l'ipertensione polmonare e l'insufficienza ventricolare destra: legatura dell'arteria polmonare sinistra e bendaggio progressivo dell'arteria polmonare principale nelle pecore

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

Large-Scale, Automated Production of Adipose-Derived Stem Cell Spheroids for 3D Bioprinting

Adipose-derived stromal/stem cells (ASCs) are a subpopulation of cells found in the stromal vascular fraction of human subcutaneous adipose tissue recognized as a classical source of mesenchymal stromal/stem cells. Many studies have been published with ASCs for scaffold-based tissue engineering approaches, which mainly explored the behavior of these cells after their seeding on bioactive scaffolds. However, scaffold-free approaches are emerging to engineer tissues in vitro and in vivo, mainly by using spheroids, to overcome the limitations of scaffold-based approaches.
Spheroids are 3D microtissues formed by the self-assembly process. They can better mimic the architecture and microenvironment of native tissues, mainly due to the magnification of cell-to-cell and cell-to-extracellular matrix interactions. Recently, spheroids are mainly being explored as disease models, drug screening studies, and building blocks for 3D bioprinting. However, for 3D bioprinting approaches, numerous spheroids, homogeneous in size and shape, are necessary to biofabricate complex tissue and organ models. In addition, when spheroids are produced automatically, there is little chance for microbiological contamination, increasing the reproducibility of the method.
The large-scale production of spheroids is considered the first mandatory step for developing a biofabrication line, which continues in the 3D bioprinting process and finishes in the full maturation of the tissue construct in bioreactors. However, the number of studies that explored the large-scale ASC spheroid production are still scarce, together with the number of studies that used ASC spheroids as building blocks for 3D bioprinting. Therefore, this article aims to show the large-scale production of ASC spheroids using a non-adhesive micromolded hydrogel technique spreading ASC spheroids as building blocks for 3D bioprinting approaches.

Here, we describe the large-scale production of adipose-derived stromal/stem cell (ASC) spheroids using an automated pipetting system to seed the cell suspension, thus ensuring homogeneity of spheroid size and shape. These ASC spheroids can be used as building blocks for 3D bioprinting approaches.

Produzione automatizzata su larga scala di sferoidi a cellule staminali di derivazione adiposa per la bioprinting 3D

Adipose-derived stromal/stem cells (ASCs) are a subpopulation of cells found in the stromal vascular fraction of human subcutaneous adipose tissue ...

In Silico Clinical Trials for Cardiovascular Disease

The SILICOFCM project mainly aims to develop a computational platform for in silico clinical trials of familial cardiomyopathies (FCMs). The unique characteristic of the platform is the integration of patient-specific biological, genetic, and clinical imaging data. The platform allows the testing and optimization of medical treatment to maximize positive therapeutic outcomes. Thus, adverse effects and drug interactions can be avoided, sudden cardiac death can be prevented, and the time between the commencement of drug treatment and the desired result can be shortened. This article presents a parametric model of the left ventricle automatically generated from patient-specific ultrasound images by applying an electromechanical model of the heart. Drug effects were prescribed through specific boundary conditions for inlet and outlet flow, ECG measurements, and calcium function for heart muscle properties. Genetic data from patients were incorporated through the material property of the ventricle wall. Apical view analysis involves segmenting the left ventricle using a previously trained U-net framework and calculating the bordering rectangle based on the length of the left ventricle in the diastolic and systolic cycle. M-mode view analysis includes bordering of the characteristic areas of the left ventricle in the M-mode view. After extracting the dimensions of the left ventricle, a finite elements mesh was generated based on mesh options, and a finite element analysis simulation was run with user-provided inlet and outlet velocities. Users can directly visualize on the platform various simulation results such as pressure-volume, pressure-strain, and myocardial work-time diagrams, as well as animations of different fields such as displacements, pressures, velocity, and shear stresses.

In Silico Clinical Trials for Cardiovascular Disease

This protocol demonstrates the workflow of the SILICOFCM platform for automatically generating a parametric model of the left ventricle from patient-specific ultrasound images by applying a multi-scale electromechanical model of the heart. This platform enables in silico clinical trials intended to reduce real clinical trials and maximize positive therapeutic outcomes.

In zona Silico Studi clinici per le malattie cardiovascolari

The SILICOFCM project mainly aims to develop a computational platform for in silico clinical trials of familial cardiomyopathies (FCMs). The unique ...

Valutazione delle proprietà idrodinamiche nelle valvole aortiche suine montate

An Ex Vivo Porcine Model for Hydrodynamic Testing of Experimental Aortic Valve Procedures and Novel Medical Devices

The options for testing new cardiac procedures and investigative medical devices prior to use in an animal model are limited. In this study, we present a method for mounting a porcine aortic valve in a pulse duplicator to evaluate its hydrodynamic properties. These properties can then be evaluated before and after the procedure under investigation is performed and/or the investigative medical device is applied. Securing the inflow segment presents some difficulty owing to the lack of circumferential myocardium in the left ventricular outflow tract. This method addresses that issue by securing the inflow segment using the anterior leaflet of the mitral valve and then suturing the left ventricular free wall around the inflow fixture. The outflow segment is secured simply by inserting the fixture into an incision in the superior aspect of the aortic arch. We found that specimens had significantly different hydrodynamic properties before and after tissue fixation. This finding induced us to use fresh specimens in our testing and should be considered when using this method. In our work, we used this method to test novel intracardiac patch materials for use in the valvular position by performing an aortic valve neocuspidization procedure (Ozaki procedure) on the mounted porcine aortic valves. These valves were tested before and after the procedure to assess the change in hydrodynamic properties in comparison to the native valve. Herein, we report a platform for hydrodynamic testing of experimental aortic valve procedures that enables comparison with the native valve and between different devices and techniques used for the procedure under investigation.

Autore in primo piano: Avanzamento dei test sulle procedure cardiache prima di intraprendere studi su animali di grossa taglia 

We present a method for mounting a porcine aortic valve on a pulse duplicator to test its hydrodynamic properties. This method can be used to determine the change in hydrodynamics after the application of an experimental procedure or novel medical device prior to use in a large animal model.

Un modello suino ex vivo per test idrodinamici di procedure sperimentali di valvole aortiche e nuovi dispositivi medici

The options for testing new cardiac procedures and investigative medical devices prior to use in an animal model are limited. In this study, we present a ...