Antithrombogenic Modification of Small-Diameter Microfibrous Vascular Grafts

Abstract

Objective-To develop small-diameter vascular grafts with a microstructure similar to native matrix fibers and with chemically modified microfibers to prevent thrombosis. Methods and Results-Microfibrous vascular grafts (1-mm internal diameter) were fabricated by electrospinning, and hirudin was conjugated to the poly (L-lactic acid) microfibers through an intermediate linker of poly(ethylene glycol). The modified microfibrous vascular grafts were able to reduce platelet adhesion/aggregation onto microfibrous scaffolds, and immobilized hirudin suppressed thrombin activity that may interact with the scaffolds. This 2-pronged approach to modify microfibrous vascular graft showed significantly improved patency (from 50% to 83%) and facilitated endothelialization, and the microfibrous structure of the vascular grafts allowed efficient graft remodeling and integration, with the improvement of mechanical property (elastic modulus) from 3.5 to 11.1 MPa after 6 months of implantation. Conclusion-Microfibrous

A Novel Ovine ex vivo Arteriovenous Shunt Model to Test Vascular Implantability

“…Endothelial cell seeding or antithrombogenic luminal surface coating has been used to avoid platelet attachment and thrombus formation [Robotin-Johnson et al, 1998;Conklin et al, 2002;Wu et al, 2007;Hashi et al, 2010]. Thrombosis initiates from a subconfluent or damaged endothelium that exposes the underlying collagen matrix leading to platelet activation and fibrin clot formation [Brass et al, 2008].…”

Novel Adult Stem Cells for Peripheral Nerve Regeneration

“…MVSCs derived from carotid arteries and jugular veins of SD rats were lysed with Trizol reagent (Invitrogen). and total RNA was extracted as previously described 36 . For microarray analysis, the RNA pellet was resuspended in nuclease-free H 2 O and was subsequently diluted to a concentration of 0.50 mg ml − 1 .…”

“…Electrospinning technique was used to produce vascular grafts and nerve conduits as previously described 25,35,36,57 . For cell transplantation into nerve conduits, MVSCs were isolated using tissue explant culture method from the carotid arteries of GFP rats.…”

Scaffolds and Cell-Based Tissue Engineering for Blood Vessel Therapy

“…A platelet adhesion test was analyzed by scanning electron microscopy and immunofluorescence staining with an anti-CD41 antibody. The patency result came from a rat model implantation [Hashi et al, 2010]. Recently, a small-caliber graft produced from polyhedral oligomeric silsesquioxane poly(carbonate-urea) urethane, which is a nanocomposite biomaterial, was shown to have greater than 60% potency after implantation into a sheep carotid artery for 9 months [Ahmed et al, 2014].…”