RESUMO
Use of extracorporeal membrane oxygenation (ECMO) for cardiorespiratory failure remains complicated by blood clot formation (thrombosis), triggered by biomaterial surfaces and flow conditions. Thrombosis may result in ECMO circuit changes, cause red blood cell hemolysis, and thromboembolic events. Medical device thrombosis is potentiated by the interplay between biomaterial properties, hemodynamic flow conditions and patient pathology, however, the contribution and importance of these factors are poorly understood because many in vitro models lack the capability to customize material and flow conditions to investigate thrombosis under clinically relevant medical device conditions. Therefore, an ECMO thrombosis-on-a-chip model is developed that enables highly customizable biomaterial and flow combinations to evaluate ECMO thrombosis in real-time with low blood volume. It is observed that low flow rates, decelerating conditions, and flow stasis significantly increased platelet adhesion, correlating with clinical thrombus formation. For the first time, it is found that tubing material, polyvinyl chloride, caused increased platelet P-selectin activation compared to connector material, polycarbonate. This ECMO thrombosis-on-a-chip model can be used to guide ECMO operation, inform medical device design, investigate embolism, occlusion and platelet activation mechanisms, and develop anti-thrombotic biomaterials to ultimately reduce medical device thrombosis, anti-thrombotic drug use and therefore bleeding complications, leading to safer blood-contacting medical devices.
Assuntos
Oxigenação por Membrana Extracorpórea , Dispositivos Lab-On-A-Chip , Ativação Plaquetária , Adesividade Plaquetária , Trombose , Oxigenação por Membrana Extracorpórea/métodos , Oxigenação por Membrana Extracorpórea/instrumentação , Trombose/etiologia , Humanos , Ativação Plaquetária/fisiologia , Plaquetas/metabolismoRESUMO
Coronary artery stents are life-saving devices, and millions of these devices are implanted annually to treat coronary heart disease. The current gold standard in treatment is drug-eluting stents, which are coated with a biodegradable polymer layer that elutes antiproliferative drugs to prevent restenosis due to neointimal hyperplasia. Stenting is commonly paired with systemic antiplatelet therapy to prevent stent thrombosis. Despite their clinical success, current stents have significant limitations including inducing local inflammation that drives hyperplasia; a lack of hemocompatibility that promotes thrombosis, increasing need for antiplatelet therapy; and limited endothelialization, which is a critical step in the healing process. In this research, we designed a novel material for use as a next-generation coating for drug-eluting stents that addresses the limitations described above. Specifically, we developed a recombinant spider silk material that is functionalized with an REDV cell-adhesive ligand, a peptide motif that promotes specific adhesion of endothelial cells in the cardiovascular environment. We illustrated that this REDV-modified spider silk variant [eADF4(C16)-REDV] is an endothelial-cell-specific material that can promote the formation of a near-confluent endothelium. We additionally performed hemocompatibility assays using human whole blood and demonstrated that spider silk materials exhibit excellent hemocompatibility under both static and flow conditions. Furthermore, we showed that the material displayed slow enzyme-mediated degradation. Finally, we illustrated the ability to load and release the clinically relevant drug everolimus from recombinant spider silk coatings in a quantity and at a rate similar to that of commercial devices. These results support the use of REDV-functionalized recombinant spider silk as a coating for drug-eluting stents.