Bare Metal Stent ferromagnetico per Capture cellule endoteliali e conservazione
Summary
I nostri obiettivi erano di progettare, produrre e testare stent ferromagnetici per la cattura delle cellule endoteliali. Dieci stent sono stati testati per la frattura e altre 10 stent sono stati testati per magnetismo mantenuto. Infine, 10 stent sono stati testati in vitro e altre 8 stent sono stati impiantati in 4 maiali per mostrare la cattura e la conservazione delle cellule.
Abstract
È necessario un rapido endotelizzazione di stent cardiovascolari per ridurre la trombosi dello stent e per evitare la terapia anti-piastrinica che può ridurre il rischio di sanguinamento. La possibilità di utilizzare forze magnetiche per catturare e trattenere le cellule endoteliali escrescenza (EOC) marcate con nanoparticelle di ossido di ferro super-paramagnetiche (spion) è stato indicato in precedenza. Ma questa tecnica richiede lo sviluppo di uno stent meccanicamente funzionale da un materiale magnetico e biocompatibile seguita da in-vitro e in vivo alcune prove endotelizzazione rapida. Abbiamo sviluppato uno stent debolmente ferromagnetico in acciaio inox 2205 duplex utilizzando computer aided design (CAD) e il suo design è stata ulteriormente raffinata con analisi agli elementi finiti (FEA). Il disegno finale dello stent mostrato una deformazione principale sotto del limite frattura del materiale durante crimpatura meccanica ed espansione. Cento stent sono stati fabbricati e un loro sottoinsieme è stato utilizzato per prove meccaniche, retained misure di campo magnetico, studi in vitro di cattura delle cellule, e in vivo studi di impianto. Dieci stent sono stati testati per la distribuzione per verificare se sono sostenuti aggraffatura e l'espansione del ciclo senza guasti. Altri 10 sono stati magnetizzati con stent un forte magnete al neodimio e il loro campo magnetico conservato è stato misurato. Gli stent hanno mostrato che il magnetismo trattenuto era sufficiente a catturare spion marcato EOC nei nostri studi de vitro. Spion marcato EOC cattura e la conservazione sono stati verificati in modelli animali di grandi dimensioni mediante l'impianto di stent 1 magnetizzato e 1 stent controllo non magnetizzato in ognuno dei 4 maiali. Le arterie stent sono stati espiantati dopo 7 giorni e analizzati istologicamente. Gli stent debolmente magnetici sviluppati in questo studio sono stati in grado di attrarre e trattenere le cellule endoteliali spion marcato che possono promuovere una rapida guarigione.
Introduction
Patients implanted with vascular stents manufactured from thrombogenic materials like stainless steel, cobalt chromium, and platinum chromium – both bare metal stents (BMS) and drug eluting stents (DES) – need anti-platelet therapy to prevent thrombus formation. BMS heal rapidly, but are subject to late stage restenosis due to incomplete healing. DES require long term anti-platelet therapy due to delayed healing. Anti-platelet therapy administered to avoid thrombosis as a result of incomplete or delayed healing leads to increased bleeding risk and may not be suitable for certain patients1,2. An ideal stent will heal completely and quickly thus avoiding long-term anti-platelet therapy and late stage restenosis. This complete healing can only be achieved if the stent is rapidly coated with a monolayer of endothelial cells after implantation. Coating the stents with biocompatible materials such as gold or other biopolymers has been shown to improve thrombo-resistance, but none of these techniques achieved ideal blood compatibility as may be possible by coating with endothelial cells3,4.
A stent can be coated with endothelial cells post implantation by attracting circulating progenitor cells. This self-seeding technique can be achieved by utilizing ligands and antibodies. But this technique is limited by the low number of circulating endothelial progenitor cells. A promising strategy is to deliver cells directly to the stent immediately following implantation during a short period of blood flow occlusion3,5. This strategy requires a technique for rapidly capturing cells and retaining them on the stent even after restoring blood flow. We have developed a technique in which a magnetic stent is used to attract and retain magnetically-labeled endothelial cells delivered post implantation. To achieve this, a functional BMS with sufficient magnetic properties to capture and retain magnetically-labeled endothelial cells is required6.
In this paper, we discuss the methods for designing, manufacturing, and testing a 2205 stainless steel stent. The stents were designed using CAD and FEA. The manufactured stents were magnetized using a neodymium magnet and the retained magnetic field was measured using a magneto-resistance microsensor probe. We then tested the stents for magnetically-labeled cell capture in a culture dish during our in-vitro experiments. Finally, the stents were tested in-vivo by implanting magnetic and non-magnetic stents in 4 pigs and histologically analyzing the stented arteries.
Protocol
Representative Results
Discussion
Abbiamo sviluppato uno stent magnetica che può funzionare come un stent di metallo nudo e in grado di attirare le cellule endoteliali spion marcato. In studi precedenti che coinvolgono stent magnetici, i ricercatori hanno usato nichel stent rivestiti commerciali e bobine o mesh in materiali magnetici a causa della indisponibilità di uno stent ferromagnetico 5,10-14. Altri gruppi hanno usato anche la natura paramagnetica attualmente in commercio stent in acciaio inox 304-grado per il targeting di nanopartice…
Declarações
The authors have nothing to disclose.
Acknowledgements
The authors thank Tyra Witt, Cheri Mueske, Brant Newman and Dr. Peter J. Psaltis, MBBS, PhD for their valuable contributions. This study was financially supported by European Regional Development Fund – FNUSA-ICRC (No. CZ.1.05/1.100/02.0123), American Heart Association Scientist Development Grant (AHA #06-35185N), National Institutes of Health (T32HL007111) and The Grainger Innovation Fund – Grainger Foundation.
Materials
| 2205 Stainless steel | Carpenter Technology Corporation | N/A | Round bar stock material |
| Abaqus | Dassault systems | N/A | Software |
| Atropine | Prescription drug. | ||
| Clopidogrel | Commercial name: Plavix. Prescription drug. | ||
| CM-DiI | Life Technologies | V-22888 | Molecular Probes, Eugene, OR |
| Endothelial growth medium-2 | Lonza | CC-3162 | |
| Hand Held Crimping tool | Blockwise engineering | M1-RMC | |
| Hydrochloric acid (HCl) | Sigma Aldrich | MFCD00011324 | CAUTION: wear proptective equipment and handle under fume hood |
| Isoflurane anesthesia | Piramal Critical Care, Inc. | ||
| Isopropyl alcohol | Sigma Aldrich | MFCD00011674 | |
| NdFeB magnet 2" Dia x 1" thick | Amazing magnets | D1000P | Axially magnetized disc magnet with poles on flat faces |
| Over-The-Wire trifold balloon | N/A | N/A | Any commercially available OTW trifold balloon can be used |
| Phosphate buffered saline | Life Technologies | 10010-023 | Commonly known as PBS |
| Sodium Bicarbonate (NaHCO3) | Sigma Aldrich | MFCD00003528 | |
| Sodium pentobarbital | Zoetis | Commercial Name: Sleepaway (26%), FatalPlus, Beuthanasi. Controlled substance to be ordered only by licensed veternarian | |
| SolidWorks | Dassault systems | N/A | Software |
| SpinTJ-020 micro sensor | MicroMagneitcs Sensible Solutions | N/A | Long probe STJ-020 microsensor |
| SPION | Mayo Clinic | N/A | Nanoparticles synthesized internally (Ref: Lee, S. J. et al. Nanoparticles of magnetic ferric oxides encapsulated with poly(D,L latide-co-glycolide) and their applications to magnetic resonance imaging contrast agent. J Magn Magn Mater 272, 2432-2433, doi:DOI 10.1016/j.jmmm.2003.12.416 (2004)) |
| Telazol | Zoetis | Controlled substance to be ordered only by licensed veternarian | |
| Trypsin EDTA | Life Technologies | 25200-056 | Gibco, Grand Island, NY |
| Xylazine | Bayer Animal Health | Commercial name: Rompun. Controlled sunstance to be ordered only by a licensed veternarian |
Referências
- Garg, S., Serruys, P. W. Coronary stents: current status. J Am Coll Cardiol. 56, 1-42 (2010).
- Austin, D., et al. Drug-eluting stents versus bare-metal stents for off-label indications: a propensity score-matched outcome study. Circ Cardiovasc Interv. 1 (1), 45-52 (2008).
- Polyak, B., et al. High field gradient targeting of magnetic nanoparticle-loaded endothelial cells to the surfaces of steel stents. P Natl Acad Sci USA. 105 (2), 698-703 (2008).
- Tassiopoulos, A. K., Greisler, H. P. Angiogenic mechanisms of endothelialization of cardiovascular implants: a review of recent investigative strategies. J Biomat Sci-Polym E. 11 (11), 1275-1284 (2000).
- Pislaru, S. V., et al. Magnetic forces enable rapid endothelialization of synthetic vascular grafts. Circulation. 114, I314-I318 (2006).
- Uthamaraj, S., et al. Design and validation of a novel ferromagnetic bare metal stent capable of capturing and retaining endothelial cells). Ann Biomed Eng. 42 (12), 2416-2424 (2014).
- Gulati, R., et al. Diverse origin and function of cells with endothelial phenotype obtained from adult human blood. Circ Res. 93 (11), 1023-1025 (2003).
- Lee, S. J., et al. Nanoparticles of magnetic ferric oxides encapsulated with poly(D,L latide-co-glycolide) and their applications to magnetic resonance imaging contrast agent. J Magn Magn Mater. 272 (3 Special Issue), 2432-2433 (2004).
- Lee, S. J., et al. Magnetic enhancement of iron oxide nanoparticles encapsulated with poly(D,L-latide-co-glycolide). Colloid Surface A. (1-3), 255-251 (1016).
- Forbes, Z. G., et al. Locally targeted drug delivery to magnetic stents for therapeutic applications. Computer Architectures for Machine Perception, 2003 IEEE International Workshop on. , 1-6 (2003).
- Rathel, T., et al. Magnetic Stents Retain Nanoparticle-Bound Antirestenotic Drugs Transported by Lipid Microbubbles. Pharm Res-Dordr. 29 (5), 1295-1307 (2012).
- Gunn, J., Cumberland, D. Stent coatings and local drug delivery – state of the art. Eur Heart J. 20 (23), 1693-1700 (1999).
- Lu, A., Jia, G., Gao, G., Wang, X. The effect of magnetic stent on coronary restenosis after percutaneous transluminal coronary angioplasty in dogs. Chin Med J (Engl. 114 (8), 821-823 (2001).
- Kempe, H., Kempe, M. The use of magnetite nanoparticles for implant-assisted magnetic drug targeting in thrombolytic therapy. Biomaterials. 31 (36), 9499-9510 (2010).
- Chorny, M., et al. Targeting stents with local delivery of paclitaxel-loaded magnetic nanoparticles using uniform fields. P Natl Acad Sci USA. 107 (18), 8346-8351 (2010).
- Polyak, B., Friedman, G. Magnetic targeting for site-specific drug delivery: applications and clinical potential. Expert Opin Drug Del. 6 (1), 53-70 (2009).
- Liu, J. Y., et al. Magnetic stent hyperthermia for esophageal cancer: an in vitro investigation in the ECA-109 cell line. Oncol Rep. 27 (3), 791-797 (2012).
- Gunn, J., Cumberland, D. Does stent design influence restenosis. Eur Heart J. 20 (14), 1009-1013 (1999).
- Aviles, M. O., et al. In vitro study of ferromagnetic stents for implant assisted-magnetic drug targeting. J Magn Magn Mater. 311 (1), 306-311 (2007).
- Mardinoglu, A., et al. Theoretical modelling of physiologically stretched vessel in magnetisable stent assisted magnetic drug targeting application. J Magn Magn Mater. 323 (3-4), 324-329 (2011).
- Liu, Z. Y., et al. Stress corrosion cracking of 2205 duplex stainless steel in H2S-CO2 environment. J Mater Sci. 44 (16), 4228-4234 (2009).
- Alverez-Armas, I., Degallaix-Moreuill, S. . Duplex stainless steels. , (2009).
- Tefft, B. J., et al. Magnetizable Duplex Steel Stents Enable Endothelial Cell Capture. Ieee T Magn. 49 (1), 463-466 (2013).
- Pelton, A. R., et al. Fatigue and durability of Nitinol stents. J Mech Behav Biomed Mater. 1 (2), 153-164 (2008).
- Knowles, M., et al. Finite element analysis of a balloon-expandable stent and superior mesenteric arterial wall interaction. J Vasc Surg. 60 (6), 1722-1723 (2014).
- Veeram Reddy, S. R., et al. A novel biodegradable stent applicable for use in congenital heart disease: bench testing and feasibility results in a rabbit model. Catheter Cardiovasc Interv. 83 (3), 448-456 (2014).
- Shellock, F. G. MR imaging of metallic implants and materials: a compilation of the literature. AJR Am J Roentgenol. 151 (4), 811-814 (1988).
- Lopic, N., et al. Quantitative determination of magnetic force on a coronary stent in MRI. J Magn Reson Imaging. 37 (2), 391-397 (2013).
