Matrix Synthesis of Human Intervertebral Disc Cells: Effect of Gene Transfer, Exogenous Growth Factor, Incubation Period, and Culture Methods / 대한척추외과학회지

ABSTRACT

STUDY DESIGN: In vitro experiment to determine the matrix synthesis of intervertebral disc (IVD) cell to various biologic interventions and conditions. OBJECTIVES: To elucidate biologic responses in terms of matrix synthesis of human IVD cells in vitro to various factors i.e. concentration of adenoviral vector and exogenous growth factor, duration of incubation, and type of culture methods. SUMMARY OF LITERATURE REVIEW Sophisticated method to delivery of growth factors, in continuous manner, is the genetic modification of disc cells through gene transfer. Direct comparison of gene transfer and exogenous growth factor on matrix synthesis has not been reported. MATERIALS AND METHODS: IVD tissue was obtained from twenty three patients. Isolation and preparation of disc cells in monolayer (D) and alginate beads (3D) culture were performed. Disc cells in 2D and 3D were treated with either Ad/TGF-beta1 or exogenous TGF-beta1. Control cultures were treated with either saline or Ad/luciferase. Matrix synthesis (newly synthesized proteoglycan) was measured in various conditions (concentration of adenoviral vector and exogenous growth factor, duration of incubation, and type of culture methods). Newly synthesized proteoglycan were analyzed using chromatography on Sephadex G-25 in PD-10 columns after S35-sulfate incorporation. RESULTS: Ad/TGF-beta1 showed increase in proteoglycan synthesis (plateau at 75MOI) in 3D culture, (plateau at 25MOI) in 2D culture. In 3D culture, Ad/TGF-beta1 showed significant increase in proteoglycan synthesis on day 1, 2, and 3 of incubation. In 2D culture, Ad/TGF-beta1 showed significant increase in proteoglycan synthesis on day 2 of incubation with significant loss of anabolic effect on day 3. In 3D culture, exogenous TGF-beta1 showed increase in proteoglycan synthesis (plateau at 2ng/ml) while in 2D culture, there is no synthetic response to exogenous TGF-beta1 CONCLUSION: Therapeutic gene transfer provided sustained and increased anabolic responses than exogenous growth factor.