Biologic and cellular treatment strategies aiming for curing intervertebral disc degeneration (IDD) have been proposed recently. Given the convenient availability and expansion potential, adipose-derived stromal cells (ADSCs) might be an ideal cell candidate. However, the interaction between ADSCs and nucleus pulposus (NP) cells still remains ambiguous, especially in direct co-cultures of the two types of cells. Nevertheless, NP markers in ADSCs after co-cultures were unidentified. Here, we addressed the interaction of human ADSCs and NP cells in a direct co-culture system for the first time. As a result, ADSCs could differentiate to the NP cell phenotype with a significant up-regulated expression of multiple genes and proteins in extracellular matrix (ECM) (SOX9, COL2A1, ACAN, and COL6A2), relative NP markers (FOXF1, PAX1, CA12, and HBB) and pertinent growth factors (CDMP-1, TGF-β1, IGF-1, and CTGF). Moreover, the gene expression of COL2A1, ACAN, and COL6A2 of degenerate NP cells was also up-regulated. Collectively, these results suggest that direct co-cultures of ADSCs and NP cells may exert a reciprocal impact, that is, both stimulating ADSCs differentiation to the NP cell phenotype and inducing NP cells to regain functional phenotype. Accordingly, ADSCs might be a potential candidate in the development of cellular treatment strategies for IDD.
Keywords: adipose-derived stem cells; direct co-culture; intervertebral disc degeneration; nucleus pulposus.
© 2013 Orthopaedic Research Society.