Effect of hypoxia-inducible VEGF gene expression on revascularization and graft function in mouse islet transplantation.
For gene transfer strategies to improve islet engraftment, vascular endothelial growth factor (VEGF) expression should be regulated in a way that matches the transient nature of revascularization with simultaneously avoiding undesirable effects of overexpression. The aim of this study was to investigate the effects of hypoxia-inducible VEGF gene transfer using the RTP801 promoter on islet grafts. We implanted pSV-hVEGF transfected, pRTP801-hVEGF transfected or nontransfected mouse islets under the kidney capsule of streptozotocin-induced diabetic syngeneic mice. Human VEGF immunostaining of day 3 grafts revealed that the pRTP801-hVEGF transfected group had higher hVEGF expression compared with the pSV-hVEGF transfected group. BS-1 staining of day 3 grafts from the pRTP801-hVEGF transfected group showed the highest vascular density, which was comparable with day 6 grafts from the nontransfected group. In 360 islet equivalent (IEQ)-transplantation which reverted hyperglycemia in all mice, the area under the curve of glucose levels during intraperitoneal glucose tolerance test 7 weeks post-transplant was lower in mice transplanted with pRTP801-hVEGF transfected grafts compared with mice transplanted with nontransfected grafts. In 220 IEQ-transplantations, diabetic mice transplanted with pRTP801-hVEGF islets became normoglycemic more rapidly compared with mice transplanted with pSV-hVEGF or nontransfected islets, and diabetes reversal rate after 50 days was 90%, 68%, and 50%, respectively. In conclusion, our results indicate that regulated overexpression of hVEGF in a hypoxia-inducible manner enhances islet vascular engraftment and preserves islet function overtime in transplants.
Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
Byung Wan
BW
Lee
Minhyung
M
Lee
Hee Young
HY
Chae
Sanghyun
S
Lee
Jun Goo
JG
Kang
Chul Sik
CS
Kim
Seong Jin
SJ
Lee
Hyung Joon
HJ
Yoo
Sung-Hee
SH
Ihm
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism; D015316:Genetic Therapy / Q000379:methods; D006085:Graft Survival; D006801:Humans; D000860:Hypoxia / Q000378:metabolism; D007515:Islets of Langerhans / Q000098:blood supply* / Q000502:physiology; D016381:Islets of Langerhans Transplantation / Q000379:methods / Q000502:physiology*; D008297:Male; D051379:Mice; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000502:physiology / Q000627:therapeutic use*
C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A