Biointegrated Synthetic Grafts for Reconstruction of Vascular Tissues

Current vascular repair and replacement grafts made from synthetic biomaterials, typically expanded polytetrafluoroethylene (ePTFE), have poor functionality for use with smaller vessels in the extremities. We propose using ?STAR? synthetic biomaterial, a well developed microporous tissue scaffold, already in human device use, to construct grafts that potentially overcome the issues with stenosis and infection that limit use of existing prosthetic graft materials. When implanted, STAR biomaterial exhibits large reductions in foreign body response, enhances angiogenesis, and concentrates natural immune cells to resist infections. These biological responses are regulated by the tightly controlled and optimized porous geometry, and do not require use of added biologics. By significantly reducing foreign body encapsulation around the graft exterior, ?STARgraft? reduces capsular contraction, a significant contributor to lumen narrowing. Use of STAR biomaterial on the inner blood-contacting surfaces offers potential to use the pore structure?s inherent proangiogenicity to facilitate capillary ingrowth and support spontaneous endothelialization. Since the biological responses to STAR biomaterial are largely independent of material chemistry, STARgraft can be constructed from well-characterized high-compliance elastomeric silicones highly suited for vascular graft use. Preliminary in vivo feasibility data in an arteriovenous shunt model suggests the approach has promise for the vascular reconstruction application.