FIG. 7.

Representative tissue engineering approaches to intervertebral disc tissue engineering. (A) Inductive approach for treating disc degeneration through dual release of dexamethasone (DEX) and transforming growth factor-β3 (TGFβ3) from polylactic co-glycolic acid (PLGA) microspheres. (B) Immunostaining for aggregan in rodent disc samples up to 24 weeks (W) postimplantation. NC, nonoperated control; DC, degeneration control; PM, injection of DEX/TGFβ3 microspheres into disc; PMA, injection of DEX/TGFβ3 microspheres coated with adipose-derived stromal cells. (C) Biomaterial approach to promote survival and retention of NP cells postinjection within polyethylene glycol (PEG)–laminin-111 (LM111) biomaterial carrier (top) or phosphate-buffered saline (PBS; bottom) (30 min and 7 days postinjection). (D) Bioreactor-based strategy to promote the maturation of engineered discs. (i) Cell-laden nanofibrous strips were rolled to make a concentric ring for AF repair; (ii) empty core space of the concentric ring was filled with a biomaterial encapsulating human NP cells and mesenchymal stem cells to form the engineered NP; (iii) disc composite constructs were cultured in a bioreactor and (iv) stimulated by direct contact compressive loading. (A, B) Reprinted from Liang et al.,¹⁰⁸ reprinted from Francisco et al.,¹¹⁰ and (D) reprinted from Tsai et al.¹⁴⁸ with permission from Elsevier.