Genetically Engineered Stem Cells for Tissue Regeneration

Genetic engineering of human stem cells for enhanced angiogenesis using biodegradable polymeric nanoparticles, 6 page pdf Genetically engineered stem cells regrew veins and help salvage damaged limbs and tissue in mice.

This study suggests that stem cells transiently modified with biodegradable polymeric nanoparticles can promote therapeutic angiogenesis. This technology may facilitate engineering and regeneration of large masses of various tissues such as bone and muscle, as well as complex structures that encompass multiple tissue types. We further hypothesize that this approach could be useful in treating other types of ischemic diseases such as myocardial infarction and cerebral ischemia.

Stem cells hold great potential as cell-based therapies to promote vascularization and tissue regeneration. However, the use of stem cells alone to promote angiogenesis remains limited because of insufficient expression of angiogenic factors and low cell viability after transplantation. Here, we have developed vascular endothelial growth factor (VEGF) high-expressing, transiently modified stem cells for the purposes of promoting angiogenesis. Nonviral, biodegradable polymeric nanoparticles were developed to deliver hVEGF gene to human mesenchymal stem cells (hMSCs) and human embryonic stem cell-derived cells (hESdCs). Treated stem cells demonstrated markedly enhanced hVEGF production, cell viability, and engraftment into target tissues. S.c. implantation of scaffolds seeded with VEGF-expressing stem cells (hMSCs and hESdCs) led to 2- to 4-fold-higher vessel densities 2 weeks after implantation, compared with control cells or cells transfected with VEGF by using Lipofectamine 2000, a leading commercial reagent. Four weeks after intramuscular injection into mouse ischemic hindlimbs, genetically modified hMSCs substantially enhanced angiogenesis and limb salvage while reducing muscle degeneration and tissue fibrosis. These results indicate that stem cells engineered with biodegradable polymer nanoparticles may be therapeutic tools for vascularizing tissue constructs and treating ischemic disease

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