Influence of age-related degeneration on regenerative potential of human nucleus pulposus cells.

Nucleus pulposus (NP) cells, sourced from herniation surgeries, may be used as a cell-based therapy for intervertebral disc (IVD) degeneration. But, both the regenerative potential of these degenerative adult NP cells and how to stimulate optimum matrix synthesis is not yet clear. The purpose of the current study was to understand the different phenotypic behaviors between degenerative adult NP cells and normal adolescent NP cells. Degenerative adult NP cells produced a significantly higher amount of proteoglycans and collagens than adolescent cells. Insulin-like growth factor-1 was the only anabolic cytokine with increased endogenous expression in degenerative adult NP cells. TGF-beta1 treatment of degenerative NP cells promoted matrix synthesis but stimulated too much type I collagen and suppressed type II collagen and aggrecan. Adult degenerative NP cells possess upregulated regenerative potential, but stimulation in addition to TGF-beta1 is needed to enhance matrix productivity and optimize the collagen expression profile.