Angiogenesis and neovascularization associated with extracellular matrix-modified porous implants

Therapies directed toward stimulation of angiogenesis seek to accelerate th e development of new blood vessels in tissues rendered dysfunctional becaus e of an insufficient microvascular supply. The goal of the current study wa s the stimulation of an angiogenic response around and within porous biomed ical implants, such as vascular grafts, constructed from a base polymer com posed of expanded polytetrafluoroethylene (ePTFE). Similar to many biomater ial, ePTFE does not elicit a significant angiogenic response and the porous interstices of this material remain avascular after implantation. Studies were performed to evaluate the ability of a tumorigenic cell line, the 804- G rat kidney cell to secrete an angiogenic extracellular matrix on and with in the porous structures of ePTFE. A rat model was used to evaluate and com pare implant-associated healing responses between nonmodified materials and extracellular matrix-modified ePTFE. Results demonstrated that, in contras t to untreated ePTFE, the matrix-modified ePTFE stimulated both angiogenesi s in implant-associated tissue and neovascularization of the pores within t he ePTFE interstices. Deposition of an insoluble matrix stimulates an angio genic response and has a potential application for the improvement of medic al device function. (C) 2001 John Wiley & Sons, Inc.