Effects of basic fibroblast growth factor and transforming growth factor-beta on maturation of human pediatric aortic cell culture for tissue engineering of cardiovascular structures

Optimal in vitro conditions are necessary for the development of a strong, well structured, and functional tissue engineered cardiovascular structure eventually designed for implantation. To further optimize in vitro conditions for cell proliferation and extracellular matrix formation in tissue engineering of cardiovascular structures, in this study, ascorbic acid and growth factors as additives to standard cell culture medium were evaluated for their effect on tissue development in vitro. Biodegradable polymer patches [polyglycolic acid (PGA) coated with poly-4-hydroxybutyrate (P4HB)] were seeded with human pediatric aortic cells and cultured for 7 and 28 days. Group A was cultured with standard medium (DMEM with 10% fetal calf serum and 1% antibiotics) supplemented with ascorbic acid; group B was cultured with standard medium plus ascorbic acid and basic fibroblast growth factor (bFGF); group C was cultured with standard medium adding ascorbic acid and transforming growth factor (TGF). Analysis of the cell seeded polymer constructs included DNA assay, collagen assay, and histologic and immunohistochemical examination for cell proliferation and collagen formation. After 7 and 28 days of culture, group B and group C showed a significantly higher DNA content compared with group A. The addition of bFGF (group B) led to a markedly higher collagen synthesis after 28 days of culture compared with the additives in groups C and A. The histologic and immunohistochemical examination also revealed a more dense, organized tissue development with pronounced matrix protein formation in the tissue engineered structures in group B after 28 days of culture. When seeded on to the polymeric scaffold, human vascular cells proliferate and form organized cell tissue after 28 days of culture. The addition of bFGF and ascorbic acid to the standard medium enhances cell proliferation and collagen synthesis on the biodegradable polymer, which leads to the formation of more mature, well organized tissue engineered structures.