Figure 7

Conceptual model of maturation and painful intervertebral disc degeneration. Results suggest that loss of notochordal cells (NCs) and maintenance of bioactive ligands is associated with growth and aging of the intervertebral disc (IVD) and not related to disease and pain. (1) Daily dynamic pressure induces differentiation of NCs into small nucleus pulposus cells (SNPCs) and increased matrix accumulation. The maintenance or increase in the production of soluble bioactive factors associated with patterning and neurovascular inhibition suggest such maturation of the nucleus pulposus (NP) can be considered a natural part of growth and aging (2), and results in the formation of the healthy adult IVD. However, a decrease in bioactive factors may result in neurovascular ingrowth and predispose the IVD to disease and pain (3). Such reductions may occur due to injury or microenvironmental changes. Furthermore, we hypothesize that that these bioactive factors have therapeutic potential and can be isolated and used to treat painful IVD degeneration (4).