Tárnok A, Mahnke A, Müller M, Zotz R J
Clinics for Pediatric Cardiology, Heart Center Leipzig, University of Leipzig, Germany.
Cytometry. 1999 Feb 15;38(1):30-9. doi: 10.1002/(sici)1097-0320(19990215)38:1<30::aid-cyto5>3.0.co;2-5.
Clinical studies suggest that stent design and surface texture are responsible for differences in biocompatibility of metallic endovascular stents. A simple in vitro experimental setup was established to test stent-induced degree of platelet and leukocyte activation and platelet-leukocyte aggregation by flow cytometry. Heparin-coated tantalum stents and gold-coated and uncoated stainless steel stents were tested. Stents were implanted into silicone tubes and exposed to blood from healthy volunteers. Platelet and leukocyte activation and percentage of leukocyte-platelet aggregates were determined in a whole-blood assay by subsequent staining for activation-associated antigens (CD41a, CD42b, CD62p, and fibrinogen binding) and leukocyte antigens (CD14 and CD45) and flow cytometric analysis. Blood taken directly after venous puncture or exposed to the silicone tube alone was used as negative controls. Positive control was in vitro stimulation with thrombin receptor activating peptide (TRAP-6). Low degree of platelet activation and significant increase in monocyte- and neutrophil-platelet aggregation were observed in blood exposed to stents (P < 0.05). In addition, leukocyte activation was induced as measured by increased CD45 and CD14 expression. Heparin coated stents continuously induced less platelet activation and leukocyte-platelet aggregation than uncoated stainless steel stents of the same length and shorter stents of the same structure. Stent surface coating and texture plays a role in platelet and leukocyte activation and leukocyte-platelet aggregation. Using this simple in vitro assay and whole blood and flow cytometry, it seems possible to differentiate stents by their potency to activate platelets and/or leukocytes. This assay could be applied for improving the biocompatibility of coronary stents.
临床研究表明，支架设计和表面纹理是金属血管内支架生物相容性差异的原因。建立了一种简单的体外实验装置，通过流式细胞术检测支架诱导的血小板和白细胞活化程度以及血小板 - 白细胞聚集情况。对肝素涂层钽支架、金涂层和未涂层不锈钢支架进行了测试。将支架植入硅胶管中，并暴露于健康志愿者的血液中。通过随后对活化相关抗原（CD41a、CD42b、CD62p和纤维蛋白原结合）和白细胞抗原（CD14和CD45）进行染色以及流式细胞术分析，在全血检测中测定血小板和白细胞活化情况以及白细胞 - 血小板聚集体的百分比。直接在静脉穿刺后采集的血液或仅暴露于硅胶管的血液用作阴性对照。阳性对照是用凝血酶受体激活肽（TRAP - 6）进行体外刺激。在暴露于支架的血液中观察到血小板活化程度较低，单核细胞和中性粒细胞 - 血小板聚集显著增加（P < 0.05）。此外，通过CD45和CD14表达增加来衡量，白细胞活化被诱导。与相同长度的未涂层不锈钢支架和相同结构的较短支架相比，肝素涂层支架持续诱导的血小板活化和白细胞 - 血小板聚集较少。支架表面涂层和纹理在血小板和白细胞活化以及白细胞 - 血小板聚集中起作用。使用这种简单的体外检测方法以及全血和流式细胞术，似乎有可能根据其激活血小板和/或白细胞的能力来区分支架。该检测方法可用于改善冠状动脉支架的生物相容性。
