水凝胶构造和纤维蛋白基胶方法来提供治疗的小鼠心肌梗死模型。
Summary
This protocol aims to alleviate the limitation of poor cell engraftment for stem cell treatment of myocardial infarctions through the use of a hydrogel system and a fibrin-based glue. With this approach, cell-to-tissue contact post-infarction can be maintained, increasing the therapeutic potential of beneficial agents at the site of injury.
Abstract
The murine MI model is widely recognized in the field of cardiovascular disease, and has consistently been used as a first step to test the efficacy of treatments in vivo1. The traditional, established protocol has been further fine-tuned to minimize the damage to the animal. Notably, the pectoral muscle layers are teased away rather than simply cut, and the thoracotomy is approached intercostally as opposed to breaking the ribs in a sternotomy, preserving the integrity of the ribcage. With these changes, the overall stress on the animal is decreased.
Stem cell therapies aimed to alleviate the damage caused by MIs have shown promise over the years for their pro-angiogenic and anti-apoptotic benefits. Current approaches of delivering cells to the heart surface typically involve the injection of the cells either near the damaged site, within a coronary artery, or into the peripheral blood stream2-4. While the cells have proven to home to the damaged myocardium, functionality is limited by their poor engraftment at the site of injury, resulting in diffusion into the blood stream5. This manuscript highlights a procedure that overcomes this obstacle with the use of a cell-encapsulated hydrogel patch. The patch is fabricated prior to the surgical procedure and is placed on the injured myocardium immediately following the occlusion of the left coronary artery. To adhere the patch in place, biocompatible external fibrin glue is placed directly on top of the patch, allowing for it to dry to both the patch and the heart surface. This approach provides a novel adhesion method for the application of a delicate cell-encapsulating therapeutic construct.
Introduction
心肌梗死（MI）被定义为血液的中断造成的主要冠状动脉的闭塞心脏的区域。从一个MI造成的损害是由于活心脏组织的重塑成非功能性疤痕组织，从而降低心脏的，或者更具体地说，左心室，击败适当的能力。这导致在血液的体积可以递送到身体与每次心跳，被称为每搏输出量，以及血液泵出心脏的与每次心跳的百分比，被称为射血分数6下降。这些以及其它缩水功能，增加了对心脏的其余部分的应变，以保持足够的功能。通常情况下，它会导致第二心脏发作，这种现象出现在个体7的约10％这增加了应变能变得如此严重。
虽然医疗实践已经发展到治疗心肌梗死的直接后果，没有任何的技术已经发展到停止，慢，或逆转组织重塑的负面影响。干然而细胞疗法已成为一个可能的途径为这样的处理，尽管它们有希望潜力，干细胞还没有被证明是成功的临床设置。一个理论为他们的缺点是无法保证的有益细胞保持在梗死足够长，以产生有利的结果5的部位。它已经显示，细胞的不超过24％被简单地注入到梗死部位存活和保持在损伤部位后1天交货2。一种可能的前景为解决这一问题的细胞保留的是开发出封装任一细胞或治疗剂，其可以被输送到受损部位的生物相容水凝胶系统。所选择的这个协议的水凝胶是聚（乙二醇）二甲基丙烯酸酯，由于其先前在电池封装公关使用ocedures然而，能够包封的任何水凝胶可以用于8。贴片直接向损伤部位的递送保证细胞与组织接触过在延长的时间周期，增加的时间长度，细胞可以提供有利的因素对底层心肌。
瓶颈的修补方法是秉承补丁到心脏表面的难度。许多团体通过各种技术，最普遍的是一个简单的缝合打结构建到心脏表面9,10已经克服了这一点。这已被证明是成功的数目，其中所述构建体是由硬的材料制成的情况下，但试图在水凝胶系统时，由于高的水浓度和接插构建体的细腻性失败。为了克服这个问题，我们已利用模仿血块形成的化学纤维蛋白胶外部粘合剂系统。纤维蛋白胶已用于许多医疗手术，INC泸硬脑膜眼泪，支气管瘘，和角膜移植，突出产品的生物相容性用作伤口的密封剂11-13。此外，血纤维蛋白已经被用于各种心脏目的，包括手术治疗左心室破裂和冠状动脉旁路手术，然而，其作为粘附胶用于心脏修补不常用14-17。的凝血酶和纤维蛋白原的结果在生物相容性胶的简单制剂，可以直接放置在一个外部心脏贴片的外侧，提供了一个可行的粘附系统，以确保补丁到心脏的相互作用。
Protocol
Representative Results
Discussion
用这种方法与鼠心肌梗死模型中，我们已经开发出一种系统，其最小化到与其它鼠心肌梗死技术相关的非心肌区域的损害。这些领域包括引起气管损伤，肌肉层的切割，并且肋的破损，以暴露胸腔。我们认为，这些变化改善整体手术结果由于采取保持尽可能多的主要结构的，包括肋和肌肉层，完整的外科手术过程中的照料。
应当指出…
Disclosures
The authors have nothing to disclose.
Acknowledgements
这一工作是由美国陆军格兰特（W81XWH-08-1-0701）和卡尔基金会医院的院士。
Materials
| Harvard Model 687 Mouse Ventilator | Harvard Apparatus | 55-0001 | |
| Inintech Biosciences LLC Dry Glass Bead Sterilizer | Fisher Scientific | NC9531961 | |
| Leica MZ6 surgical microscope | Leica | ||
| Cautery Kit | Gemini | GEM 5917 | |
| Delicate Forceps – 0.4mm Tips Angled | Fine Science Tools | 11063-07 | |
| Agricola Retractor – 3.5cm Spread | Fine Science Tools | 17005-04 | |
| Spring Scissors – 2.5mm Blades Straight | Fine Science Tools | 15000-08 | |
| Castroviejo Needle Holder – w/Lock Tungsten Carbide 14cm | Fine Science Tools | 12565-14 | |
| Iris Scissors – Delicate Straight 10.5 cm | Fine Science Tools | 14060-10 | |
| 8-0 monofilament suture | Ethicon | 8730P | |
| 6-0 Silk suture | Ethicon | 639G | |
| Thrombin | Sigma | T7009 | |
| Fibrinogen | Sigma | F3879 | |
| Vetbond Tissue Adhesive | 3M | 1469SB |
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