Endothelial cell proliferation and progenitor maturation by fibrin-bound VEGF variants with differential susceptibilities to local cellular activity

Martin Ehrbar, Andrew Metters, Prisca Zammaretti, Jeffrey A. Hubbell, Andreas H. Zisch

Research output: Contribution to journalArticlepeer-review

135 Scopus citations


A number of vascular therapies could benefit from advanced methods for presentation of angiogenic growth factors, including growth of endothelium on small caliber vascular grafts and revascularization of ischemic tissue through induction of collateral vessels and microvessels. To explore methods to optimize the presentation and release of angiogenic factors in such applications in device integration and tissue repair, we studied three variant forms of vascular endothelial growth factor 121 (VEGF 121), each with differential susceptibility to local cellular proteolytic activity, formulated within fibrin matrices. (1) The prototypic variant α 2PI 1-8- VEGF 121 remains immobilized in fibrin matrices until its liberation by cell-associated enzymes, such as plasmin, that degrade the fibrin network [slow, cell-demanded release; J. Control. Release 72 (2001) 101-113]; the α 2PI 1-8 domain serves as a site for covalent attachment to fibrin during coagulation. (2) We created a new VEGF variant, α 2PI 1-8-Pla-VEGF 121 that couples to fibrin via a plasmin-sensitive sequence (Pla). Cleavage of this target site by plasmin enables direct release of α 2PI 1-8-Pla- VEGF 121 from bulk matrix degradation (accelerated, cell-demanded release). (3) Native VEGF 121 (burst, passive release) was considered as a reference. VEGF release profiles were determined experimentally as well as mathematically, α 2PI 1-8-Pla-VEGF 121 being released ca. fourfold more quickly than α 2PI 1-8-VEGF 121, both being retained compared to native VEGF 121; the differences in release could be accounted for based on knowledge of the plasmin sensitivity of the bound growth factor and the structure of the fibrin network. The bound factors were competent in inducing endothelial cell proliferation, the matrix-bound forms being more effective than native VEGF 121; as well as competent in inducing endothelial progenitor cell maturation into endothelial cells. These matrix-bound variants of VEGF 121 may be particularly useful where retention in locally applied surgical sites is desired, such as prevention of washout from vascular graft coatings and slowing loss from tissue ingrowth matrices used in local tissue revascularization and repair.

Original languageEnglish (US)
Pages (from-to)93-109
Number of pages17
JournalJournal of Controlled Release
Issue number1-3 SPEC. ISS.
StatePublished - Jan 3 2005


  • Controlled release
  • Endothelial progenitor cells
  • Fibrin
  • Graft endothelialization
  • Proteolysis
  • VEGF

ASJC Scopus subject areas

  • Pharmaceutical Science


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