Sigler M, Paul T, Grabitz R G
Herzzentrum Göttingen, Pädiatrische Kardiologie und Intensivmedizin, Georg-August-Universität Göttingen, 37099 Göttingen, Germany.
Z Kardiol. 2005 Jun;94(6):383-91. doi: 10.1007/s00392-005-0231-4.
Interest in information on biocompatibility of implants is increasing. The purpose of this paper is to discuss methods and results of pathological biocompatibility screening of explanted cardiovascular implants.
Use of standard histology after embedding in paraffin is limited since metallic implants have to be removed during workup with disruption of the specimen. Alternatively, tissue blocks containing an implant can be embedded in methylmethacrylate or hydroxyethylmethacrylate and processed by sectioning with a diamond cutter and grinding, thus leaving the implant in situ and saving the tissue/implant interface for detection of local inflammatory reactions. Another important aspect of evaluation is the progress of thrombus organisation after initial fibrin clotting on the metal surface or in the inner part of occlusion devices. New methacrylate resins and embedding techniques allow for specific immunohistochemical staining of the specimen thus enabling characterisation of tissues surrounding the implant. Information on endothelialisation of the vascular surface of the implant can be obtained by means of immunohistochemistry or by scanning electron microscopy.
Illustrating the use of these technologies, we demonstrate findings in tissue specimens from animal studies with different types of devices (i.e. stents, occlusion devices). We present corresponding findings in human specimens with implants that were removed during corrective surgery for congenital heart defects. Early endothelialisation of the vascular surface was seen after implantation in all types of devices. Cells within occlusion devices could be characterised histologically and immunohistochemically as fibromuscular cells as seen in intimal hyperplasia after stent implantation. Inflammatory implant-host reactions ranged from mild to moderate (medical grade stainless steel, nitinol) to severe (polytetrafluoroethylene [PTFE]).
With an optimal work-up of cardiovascular implants, ingrowth and endothelialisation as well as inflammatory reactions in the surrounding tissue can be assessed. This information allows evaluation of individual tissue reactions to the implant and may serve as valuable basis for optimisation of biocompatibility by implant modification.
人们对植入物生物相容性信息的关注度日益增加。本文旨在探讨取出的心血管植入物病理生物相容性筛查的方法及结果。
由于在石蜡包埋后的标准组织学检查中，金属植入物在处理过程中必须移除，这会破坏标本，因此其应用受限。另外，含有植入物的组织块可包埋于甲基丙烯酸甲酯或羟乙基甲基丙烯酸甲酯中，通过用金刚石切片机切片和研磨进行处理，从而使植入物留在原位，并保留组织/植入物界面以检测局部炎症反应。评估的另一个重要方面是在金属表面或闭塞装置内部最初形成纤维蛋白凝块后血栓组织化的进程。新的甲基丙烯酸酯树脂和包埋技术允许对标本进行特异性免疫组织化学染色，从而能够对植入物周围的组织进行特征描述。可通过免疫组织化学或扫描电子显微镜获得关于植入物血管表面内皮化的信息。
为说明这些技术的应用，我们展示了来自不同类型装置（即支架、闭塞装置）动物研究的组织标本中的发现。我们还展示了在先天性心脏缺陷矫正手术中取出的植入物的人体标本中的相应发现。在所有类型的装置植入后，均可见血管表面早期内皮化。闭塞装置内的细胞在组织学和免疫组织化学上可被表征为纤维肌细胞，这与支架植入后内膜增生中所见的情况相同。植入物与宿主的炎症反应从轻度到中度（医用级不锈钢、镍钛合金）到重度（聚四氟乙烯[PTFE]）不等。
通过对心血管植入物进行优化处理，可以评估其向内生长、内皮化以及周围组织的炎症反应。这些信息有助于评估个体组织对植入物的反应，并可为通过植入物改良优化生物相容性提供有价值的依据。
