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Proc Natl Acad Sci U S A. 2014 May 13;111(19):6952-7. doi: 10.1073/pnas.1404605111. Epub 2014 Apr 28.

Long-lasting fibrin matrices ensure stable and functional angiogenesis by highly tunable, sustained delivery of recombinant VEGF164.

Author information

1
Cell and Gene Therapy, Department of Biomedicine, University of Basel, and Department of Surgery, Basel University Hospital, CH-4031 Basel, Switzerland;
2
Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Austrian Cluster for Tissue Regeneration, Allgemeine Unfallversicherungsanstalt, A-1200 Vienna, Austria;
3
Institute of Bioengineering, School of Life Sciences and School of Engineering, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland;
4
Departments of Urology and.
5
Obstetrics, Zurich University Hospital, CH-8091 Zurich, Switzerland; andUniversity of Louisville School of Dentistry, Louisville, KY 40202.
6
Obstetrics, Zurich University Hospital, CH-8091 Zurich, Switzerland; and.
7
Cell and Gene Therapy, Department of Biomedicine, University of Basel, and Department of Surgery, Basel University Hospital, CH-4031 Basel, Switzerland; Andrea.Banfi@usb.ch.

Abstract

Clinical trials of therapeutic angiogenesis by vascular endothelial growth factor (VEGF) gene delivery failed to show efficacy. Major challenges include the need to precisely control in vivo distribution of growth factor dose and duration of expression. Recombinant VEGF protein delivery could overcome these issues, but rapid in vivo clearance prevents the stabilization of induced angiogenesis. Here, we developed an optimized fibrin platform for controlled delivery of recombinant VEGF, to robustly induce normal, stable, and functional angiogenesis. Murine VEGF164 was fused to a sequence derived from α2-plasmin inhibitor (α2-PI1-8) that is a substrate for the coagulation factor fXIIIa, to allow its covalent cross-linking into fibrin hydrogels and release only by enzymatic cleavage. An α2-PI1-8-fused variant of the fibrinolysis inhibitor aprotinin was used to control the hydrogel degradation rate, which determines both the duration and effective dose of factor release. An optimized aprotinin-α2-PI1-8 concentration ensured ideal degradation over 4 wk. Under these conditions, fibrin-α2-PI1-8-VEGF164 allowed exquisitely dose-dependent angiogenesis: concentrations ≥25 μg/mL caused widespread aberrant vascular structures, but a 500-fold concentration range (0.01-5.0 μg/mL) induced exclusively normal, mature, nonleaky, and perfused capillaries, which were stable after 3 mo. Optimized delivery of fibrin-α2-PI1-8-VEGF164 was therapeutically effective both in ischemic hind limb and wound-healing models, significantly improving angiogenesis, tissue perfusion, and healing rate. In conclusion, this optimized platform ensured (i) controlled and highly tunable delivery of VEGF protein in ischemic tissue and (ii) stable and functional angiogenesis without introducing genetic material and with a limited and controllable duration of treatment. These findings suggest a strategy to improve safety and efficacy of therapeutic angiogenesis.

PMID:
24778233
PMCID:
PMC4024904
DOI:
10.1073/pnas.1404605111
[Indexed for MEDLINE]
Free PMC Article

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