Nucleus pulposus tissue engineering: a brief review.

Symptomatic intervertebral disc degeneration is associated with several spinal diseases, which cause losses of life quality and money. Tissue engineering provides a promising approach to recover the functionality of the degenerative intervertebral disc. Most studies are directed toward nucleus pulposus (NP) tissue engineering because disc degeneration is believed to originate in NP region, and considerable progress has been made in the past decade. Before this important technique is utilized for clinical treatment of disc degeneration, many challenges need to address including in all three principal components of tissue engineering, i.e., seed cells, signals and biomaterial scaffolds. This article briefly gives certain aspects of state of the art in this field, as well as pays a little more attention to our work published in the past 5 years, on growth and differentiation factor-5 (GDF-5), adipose-derived stem cells (ADSCs) and heparin functionalization of scaffold. We suggest that combinatorial application of ADSCs, GDF-5, heparin functionalization and injectable hydrogels will be advantageous in NP tissue engineering.