Tissue plasminogen activator enhances mobilization of endothelial progenitor cells and angiogenesis in murine limb ischemia.
BACKGROUND
It has been reported that plasmin induces migration of endothelial cells. We hypothesized that tissue plasminogen activator (tPA) enhanced endothelial progenitor cell (EPC) mobilization from bone marrow (BM) into the circulation and angiogenesis in murine critical limb ischemia (CLI).


METHODS
Forty male B6 mice were randomly divided into group 1 (control), group 2 [control+recombinant tPA (intra-venous 4 mg/kg)], group 3 (CLI) and group 4 (CLI+tPA).


RESULTS
The results demonstrated higher MMP-9 activity in BM and circulatory SDF-1α level in groups 2 and 3 than in group 1, and highest in group 4 (all p<0.01) at 18 h after CLI. Compared with circulation, SDF-1α level in BM showed an opposite trend (all p<0.03). The circulating EPC (C-kit/CD31, Sca-1/KDR, CXCR4/CD34) levels at 18 h after CLI were higher in group 2 than in groups 1 and 3, and highest in group 4 (all p<0.03). EPC (C-kit/CD31, Sca-1/KDR) levels in BM were lower in group 1 than in groups 2 to 4 (all p<0.03), whereas number of CXCR4/CD34-positive EPCs in BM did not differ among the four groups at 18 h after CLI. Protein expressions of SDF-1α, CXCR4, eNOS, and VEGF, numbers of CD31+, CXCR4+, SDF-1α+, and vWF+ cells through immunofluorescent staining, numbers of small vessels (<15 μm) and blood flow measured by Laser Doppler in an ischemic area were significantly higher in group 4 than in group 3 (all p<0.005) at day 14 after CLI.


CONCLUSIONS
tPA treatment enhanced number of circulating EPCs, angiogenesis, and blood flow to ischemic tissue in a murine model of limb ischemia.
Division of Cardiology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
Hon-Kan
HK
Yip
Cheuk-Kwan
CK
Sun
Tzu-Hsien
TH
Tsai
Jiunn-Jye
JJ
Sheu
Ying-Hsien
YH
Kao
Yu-Chun
YC
Lin
Yow-Ling
YL
Shiue
Yung-Lung
YL
Chen
Han-Tan
HT
Chai
Sarah
S
Chua
Sheung-Fat
SF
Ko
Steve
S
Leu
D000818:Animals; D002465:Cell Movement / Q000187:drug effects* / Q000502:physiology; D042783:Endothelial Cells / Q000187:drug effects* / Q000502:physiology; D006614:Hindlimb / Q000098:blood supply / Q000187:drug effects; D007511:Ischemia / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018919:Neovascularization, Physiologic / Q000187:drug effects* / Q000502:physiology; D011897:Random Allocation; D013234:Stem Cells / Q000187:drug effects* / Q000502:physiology; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage*
D010959:Tissue Plasminogen Activator