Differentiation enhancement of ADSC in scaffolds with IGF-1 gene impregnation under dynamic microenvironment

Biochemical and mechanical signals enabling cardiac regeneration can be elucidated by using in vitro tissue engineering models. It was hypothesized that human insulin-like growth factor-1 (IGF-1) and three dimensional dynamic microenvironment could act independently and interactively to enhance the survival and differentiation of adipose tissue-derived stem cells (ADSCs) and hence the construction of engineered cardiac grafts. IGF-1 can be expressed by the ADSCs through genetic modification, which can be conveniently realized by incorporating the relevant genes into the three dimensional scaffold. ADSCs were cultured on three dimensional porous scaffolds with or without plasmid DNA PIRES2-IGF-1 in cardiac media, in dishes and in a spinning flask bioreactor respectively. Cell viability, formation of cardiac like structure, expression of functional proteins, and gene expressions were testified to the cultured constructs on day 14. The results showed that dynamic microenvironment enhanced the release of plasmid DNA; the ADSCs can be transfected by the released plasmid DNA PIRES2-IGF-1 in scaffold; IGF-1 had beneficial effects on the cellular viability and the increase of total protein; and it also increased the expressions of cardiac specific proteins and genes in the grafts. It was also demonstrated that dynamic stirring environment could promote the proliferation of ADSCs. Therefore, IGF-1, expressed by ADSCs transfected by DNA PIRES2-IGF-1 incorporated into scaffold, and hydrodynamic microenvironment can independently and interactively increase cellular viability, and interactively increased the expressions of cardiac specific proteins and genes in the grafts. The results would be useful for developing tissue engineered grafts for myocardial repair.