Surface Coating of Polytetrafluoroethylene with Extracellular Matrix and Anti-CD34 Antibodies Facilitates Endothelialization and Inhibits Platelet Adhesion Under Sheer Stress

Abstract

Expanded polytetrafluoroethylene (ePTFE) polymers do not support endothelialization because of nonconductive characteristics towards cellular attachment. Inner surface modification of the grafts can improve endothelialization and increase the long-term patency rate of the ePTFE vascular grafts. Here we reported a method of inner-surface modification of ePTFE vascular graft with extracellular matrix (ECM) and CD34 monoclonal antibodies (CD34 mAb) to stimulate the adhesion and proliferation of circulating endothelial progenitor cells on ePTFE graft to enhance graft endothelialization. The inner surface of ECM-coated ePTFE grafts were linked with CD34 mAb in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide (EDC/NHS) solution and the physicochemical properties, surface morphology, biocompatibility, and hemocompatibility of the grafts were studied. The hydrophilicity of CD34 mAb-coated graft inner surface was significantly improved. Fourier transform infrared spectroscopy analysis confirmed ECM and CD34 mAb cross-linking in the ePTFE vascular grafts with our method. Scanning electron microscopy analysis showed protein layer covering uniformly on the inner surface of the modified grafts. The cell-counting kit-8 (CCK-8) assay confirmed that the modified graft has no obvious cytotoxicity. The modified graft showed a low hemolytic rate (0.9%) in the direct contact hemolysis test, suggesting the modification improved hemocompatibility of biopolymers. The modification also decreased adhesion of platelets, while significantly increased the adhesion of endothelial cells on the grafts. We conclude that our method enables ePTFE polymers modification with ECM and CD34 mAb, facilitates endothelialization, and inhibits platelet adhesion on the grafts, thus may increase the long-term patency rate of the prosthetic bypass grafts. Keywords ePTFE vascular grafts Á Anti-CD34 antibody Á Extracellular matrix Á EDC/NHS solution Á Endothelial cells Lei Chen and Haipeng He are co-first authors.

Progressive Reinvention or Destination Lost? Half a Century of Cardiovascular Tissue Engineering

“…After it had been shown that the cellular source of “fall out” healing was predominantly from endothelial precursor cells in the bone marrow ( 347 , 348 ) and that these endothelial progenitor cells (EPCs) express amongst other ligands the vascular endothelial growth factor receptor VEGFR-2, as well as the CD133 and CD34 antigens ( 349 – 351 ) several attempts were made to augment the homing of these cells onto “non-vital” synthetic grafts by immobilizing anti-ligand antibodies on the surface ( 352 , 353 ) including antibodies against chemotaxis stimulating receptors on stem cells ( 354 ). Yet, even with sporadic studies showing an enhanced recruitment of circulating cells ( 349 , 355 ), without a broad consensus to focus on endothelialisation and cell population from the circulation, this approach will continue to remain an unrealised promise. As such, transmural ingrowth and endothelialisation remain the most realistic modes of tissue regeneration for synthetic scaffolds.…”

Controllable synthesis of biomimetic nano/submicro-fibrous tubes for potential small-diameter vascular grafts

“…Moreover, As shown in Table 1, all grafts exhibit a hemolysis rate much lower than 1%. The hemolysis rate of BC/CA-2 is 0.28%, which is lower than those of the ePTFE vascular graft (0.9%) reported by Chen et al 49 and an electrospun spider silk protein/PCL/ gelatin graft (0.3%) reported by Xiang et al 50 The formation of a complete endothelial layer on the surface of vascular grafts is crucially important to enhance long-term patency. 45,51 Endothelialization was monitored in vitro by seeding HUVECs onto BC, CA, and BC/CA grafts.…”

Vascular Tissue Engineering: Polymers and Methodologies for Small Caliber Vascular Grafts

“…It is widely used in VTE for the development of grafts of a medium or large diameter, with a few of them being used for <6 mm scaffolds. The small diameter PTFE scaffolds show a high failure rate due to the formation of thrombi within them ( 95 ). These events occur because of the high hydrophobicity of PTFE, which favors platelet adhesion and activation of the coagulation cascade.…”

“…The presence of antibodies improved the hydrophilicity and decreased platelet adhesion on the scaffolds. In addition, the association of antibodies and ECM facilitated endothelization, adhesion and proliferation of endothelial cells ( 95 ). In another study, PTFE was associated with PEG.…”