Combination of stromal-derived factor-1alpha and vascular endothelial growth factor gene-modified endothelial progenitor cells is more effective for ischemic neovascularization.
BACKGROUND
Recruitment and entrapment of bone marrow-derived endothelial progenitor cells (EPCs) is important in vascular endothelial growth factor (VEGF)-induced angiogenesis. EPC mobilization and differentiation are modulated by stromal-derived factor-1alpha (SDF-1alpha/CXCL12), another important chemokine. In this study, we investigated the hypothesis that SDF-1alpha and VEGF might act synergistically on EPC-mediated vasculogenesis.


METHODS
EPCs were isolated and cultured from human peripheral blood, then transduced with retroviral vectors pBabe containing human VEGF(165) complimentary DNA (Td/V-EPCs) and pBabe wild-type (Td/p-EPCs). EPC migration activity was investigated with a modified Boyden chamber assay. EPC apoptosis induced by serum starvation was studied by annexin V assays. The combined effect of local administration of SDF-1alpha and Td/V-EPC transplantation on neovascularization was investigated in a murine model of hind limb ischemia.


RESULTS
Over-expression of hVEGF(165) increased SDF-1alpha-mediated EPC migration. SDF-1alpha-mediated migration was significantly increased when EPCs were modified with VEGF (Td/V-EPCs) vs when VEGF was not present (Td/p-EPCs) or when VEGF alone was present (Td/V-EPCs; 196.8 +/- 15.2, 81.2 +/- 9.8, and 67.4 +/- 7.4/mm(2), respectively P < .001). SDF-1alpha combined with VEGF reduced serum starvation-induced apoptosis of EPCs more than SDF-1alpha or VEGF alone (P < .001). To determine the effect of this combination in vivo, SDF-1alpha was locally injected alone into the ischemic hind limb muscle of nude mice or combined with systemically injected Td/V-EPCs. The SDF-1alpha plus VEGF group showed significantly increased local accumulation of EPCs, blood-flow recovery, and capillary density compared with the other groups. The ratio of ischemic/normal blood flow in Td/V-EPCs plus SDF-1alpha group was significantly higher (P < .01), as was capillary density (capillaries/mm(2)), an index of neovascularization (Td/V-EPCs plus SDF-1alpha group, 863 +/- 31; no treatment, 395 +/-13; SDF-1alpha, 520 +/- 29; Td/p-EPCs, 448 +/- 28; Td/p-EPCs plus SDF-1alpha, 620 +/- 29; Td/V-EPCs, 570 +/- 30; P < .01). To investigate a possible mechanistic basis, we showed that VEGF up-regulated the receptor for SDF-1alpha, CXCR4, on EPCs in vitro.


CONCLUSIONS
The combination of SDF-1alpha and VEGF greatly increases EPC-mediated angiogenesis. The use VEGF and SDF-1alpha together, rather than alone, will be a novel and efficient angiogenesis strategy to provide therapeutic neovascularization.
Yu
Jian-Xing
JX
Department of Vascular Surgery, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China.
Huang
Xue-Fei
XF
Lv
Wei-Ming
WM
Ye
Cai-Sheng
CS
Peng
Xin-Zhi
XZ
Zhang
Hui
H
Xiao
Long-Bin
LB
Wang
Shen-Ming
SM
D000818:Animals; D017209:Apoptosis; D002454:Cell Differentiation; D002465:Cell Movement; D002478:Cells, Cultured; D054377:Chemokine CXCL12 / Q000008:administration & dosage / Q000494:pharmacology*; D003131:Combined Modality Therapy; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000473:pathology / Q000637:transplantation*; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006614:Hindlimb; D006801:Humans; D007273:Injections, Intramuscular; D007511:Ischemia / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D017078:Laser-Doppler Flowmetry; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D018482:Muscle, Skeletal / Q000098:blood supply*; D018919:Neovascularization, Physiologic; D012039:Regional Blood Flow; D012190:Retroviridae / Q000235:genetics; D033581:Stem Cell Transplantation; D013997:Time Factors; D014161:Transduction, Genetic; D042461:Vascular Endothelial Growth Factor A / Q000097:blood / Q000235:genetics / Q000378:metabolism*
D054377:Chemokine CXCL12; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A