A quick and effective modification method to improve the patency and endothelialization of cryopreserved allogenic blood vessels

Abstract

Cryopreserved allogeneic blood vessels have received considerable attention for vascular reconstruction owing to their easy availability and excellent anti-infective property. However, current cryopreservation methods cause significant endothelium loss alongside directly exposing smooth muscle cells and extracellular matrix components to the circulating blood, which can induce thrombosis and/or restenosis. We covalently coupled PEGylated phospholipids (DMPE-PEG) with anti-coagulant bivalirudin (abbreviated as DPB) and endothelial progenitor cell (EPC)-capturing TPSLEQRTVYAK (TPS) (abbreviated as DPT), respectively. Both DPT and DPB were co-modified onto the lumen surface of cryopreserved allogeneic vessels through hydrophobic interaction between DMPE-PEG and the phospholipid bilayer of surviving cells. Cy7-labled DMPE-PEG was used to investigate the saturation concentration and incubation time on the lumen surface of cryopreserved vessels. DPB and DPT co-modified cryopreserved vessels were characterized through different assays, including tissue viability and gene expression, hemocompatibility, and EPC capture in vitro and an artery implantation model in vivo. Co-modification of DPB and DPT attained luminal saturation as earlier as 10 min while preserving the viability of the residual cells on the cryopreserved vessels. The optimally co-modified cryopreserved allogeneic vessels showed that the DPB can improve the hemocompatibility by reducing fibrinogen adsorption and platelets adhesion alongside protecting the EPCs-capturing function of the DPT via inhibiting the masking by blood components, which altogether promoted the patency and endothelialization. This work provided a quick, biocompatible and an effective approach to functionalize tissue-engineered constructs containing alive cells.