铁磁金属裸支架对血管内皮细胞捕获和保留
Summary
我们的目标是设计，制造和测试铁支架内皮细胞捕获。十支架进行了测试骨折10多个支架进行了测试保留磁性。最后，10支架体外测试和8个支架植入4头显示细胞捕获和保留。
Abstract
心血管支架的快速内皮化是必要的，以减少支架血栓，并避免抗血小板疗法可减少出血的危险。利用磁力来捕捉和保留标记与超顺磁性氧化铁纳米颗粒（SPION）内皮细胞生长（EOC）的可行性先前已经证明。但该技术需要一个机械官能支架由磁性和生物相容性材料随后在体外和体内试验证明快速内皮化的发展。我们开发了从2205双相不锈钢弱磁性支架采用计算机辅助设计（CAD）和它的设计采用有限元分析（FEA）进一步完善。支架的最终设计在机械卷边和扩张呈现下面的材料的断裂极限一个主应变。一百支架被制造和它们的子集被用于机械测试，保留ained磁场测量，体外细胞捕获的研究，并在体内植入研究。十支架进行了测试部署，以验证他们是否持续的压接和膨胀循环无故障。另有10支架均采用强大的钕磁磁化，其保留的磁场进行了测量。该支架表明，该保留的磁性足以捕捉SPION标记的EOC 在我国的体外研究 。 SPION标记EOC采集和保留的大动物模型通过植入1磁化支架和各4头1个非磁化控制支架进行了验证。 7天后的支架的动脉植和组织学分析。在这项研究中开发的弱磁性支架有能力吸引和留住SPION标记的内皮细胞可促进快速愈合。
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
我们开发了一种磁性支架可以用作裸金属支架，能够吸引SPION标记的内皮细胞。在涉及磁支架先前的研究中，研究人员已经使用由磁性材料制成的镍涂覆的商业支架和线圈或网格，由于强磁性支架5,10-14的不可用性。其它基团也用于靶向纳米颗粒加载内皮细胞3市售304级不锈钢支架的顺磁性性质。镍涂层可以是过敏于接收到所述支架的患者和所述顺磁性支架需要的外部磁场，以吸引?…
Disclosures
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 |
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