Arteriogenic therapy based on simultaneous delivery of VEGF-A and FGF4 genes improves the recovery from acute limb ischemia

BACKGROUND: Gene therapy stimulating the growth of blood vessels is considered for the treatment of peripheral and myocardial ischemia. Here we aimed to achieve angiogenic synergism between vascular endothelial growth factor-A (VEGF-A, VEGF) and fibroblast growth factor 4 (FGF4) in murine normoperfused and ischemic limb muscles. METHODS: Adeno-associated viral vectors (AAVs) carrying β-galactosidase gene (AAV-LacZ), VEGF-A (AAV-VEGF-A) or two angiogenic genes (AAV-FGF4-IRES-VEGF-A) were injected into the normo-perfused adductor muscles of C57Bl/6 mice. Moreover, in a different experiment, mice were subjected to unilateral hindlimb ischemia by femoral artery ligation followed by intramuscular injections of AAV-LacZ, AAV-VEGF-A or AAV-FGF4-IRES-VEGF-A below the site of ligation. Post-ischemic blood flow recovery was assessed sequentially by color laser Doppler. Mice were monitored for 28 days. RESULTS: VEGF-A delivered alone (AAV-VEGF-A) or in combination with FGF4 (AAV-FGF4-IRES-VEGF-A) increased the number of capillaries in normo-perfused hindlimbs when compared to AAV-LacZ. Simultaneous overexpression of both agents (VEGF-A and FGF4) stimulated the capillary wall remodeling in the non-ischemic model. Moreover, AAV-FGF4-IRES-VEGF-A faster restored the post-ischemic foot blood flow and decreased the incidence of toe necrosis in comparison to AAV-LacZ. CONCLUSIONS: Synergy between VEGF-A and FGF4 to produce stable and functional blood vessels may be considered a promising option in cardiovascular gene therapy

PPAR\gamma activation but not PPAR\gamma haplodeficiency affects proangiogenic potential of endothelial cells and bone marrow-derived progenitors

Background. Peroxisome proliferator-activated receptor-? (PPAR?) agonists, which have been used as insulin sensitizers in diabetic patients, may improve functions of endothelial cells (ECs). We investigated the effect of PPAR? on angiogenic activities of murine ECs and bone marrow-derived proangiogenic cells (PACs). Methods. PACs were isolated from bone marrow of 10¿12 weeks old, wild type, db/db and PPAR? heterozygous animals. Cells were cultured on fibronectin and gelatin coated dishes in EGM-2MV medium. For in vitro stimulations, rosiglitazone (10 ?mol/L) or GW9662 (10 ?mol/L) were added to 80% confluent cell cultures for 24 hours. Angiogenic potential of PACs and ECs was tested in vitro and in vivo in wound healing assay and hind limb ischemia model. Results. ECs and PACs isolated from diabetic db/db mice displayed a reduced angiogenic potential in ex vivo and in vitro assays, the effect partially rescued by incubation of cells with rosiglitazone (PPAR? activator). Correction of diabetes by administration of rosiglitazone in vivo did not improve angiogenic potential of isolated PACs or ECs. In a hind limb ischemia model we demonstrated that local injection of conditioned media harvested from wild type PACs improved the blood flow restoration in db/db mice, confirming the importance of paracrine action of the bone marrow-derived cells. Transcriptome analysis showed an upregulation of prooxidative and proinflammatory pathways, and downregulation of several proangiogenic genes in db/db PACs. Interestingly, db/db PACs had also a decreased level of PPAR? and changed expression of PPAR?-regulated genes. Using normoglycemic PPAR?+/? mice we demonstrated that reduced expression of PPAR? does not influence neovascularization either in wound healing or in hind limb ischemia models. Conclusions. In summary, activation of PPAR? by rosiglitazone improves angiogenic potential of diabetic ECs and PACs, but decreased expression of PPAR? in diabetes does not impair angiogenesis