Elucidation of Endothelial Cell Hemostatic Regulation with Integrin-Targeting Hydrogels

Despite advances in the development of materials for cardiovascular devices, current strategies generally lack the thromboresistance of the native endothelium both in terms of efficacy and longevity. To harness this innate hemostatic regulation and improve long-term hemocompatibility, biohybrid devices are designed to promote endothelialization. Much of the research effort to date has focused on the use of extracellular matrix (ECM)-mimics and coatings to promote endothelial cell adhesion and migration with less attention given to the effect of the supported ECM binding events on hemostatic regulation. In this study, we developed integrin-targeted hydrogels to investigate the individual and combined effects of integrin binding events supported by many ECM-based coatings (α1β1, α2β1, α5β1, αvβ3). Targeted endothelial cell integrin interactions were first confirmed with antibody blocking studies and then correlated with gene expression of hemostatic regulators and a functional assay of platelet attachment and activation. Surfaces that targeted integrins α1β1 and α2β1 resulted in an endothelial cell layer that exhibited a thromboresistant phenotype with an associated reduction in platelet attachment and activation. It is anticipated that identification of specific integrins that promote endothelial cell adhesion as well as thromboresistance will enable the design of cardiovascular materials with improved long-term hemocompatibility.