Introduction: Recent studies have shown encouraging progress toward the use of syngenic and allogenic mesenchymal stromal cell (MSCs) to arrest, or even reconstruct the normal structure and function of degenerated intervertebral discs (IVDs) in various animal models. Here we demonstrate that human adipose-derived mesenchymal stromal cells (Ad-MSCs) modulate the inflammatory response of degenerated IVD and differentiate into a chondrogenic fate.

Patients and Methods: IVD fragments obtained from patients undergoing discectomy were placed on the bottom layer of a 12-wells co-colture system, while Ad-MSCs were placed on the upper layer. At different time-point co-colture medium was harvested and human cytokines were detected and analysed using a multiplex bead-based assays. To verify the Ad-MSCs differentiation into a chondrogenic fate, RNA isolated from Ad-MSCs co-coltured in presence of IVD fragments was analysed by RT-PCR analysis.

Results: Herein we tested the capability of human adipose-derived mesenchymal stromal cells (Ad-MSCs) to modulate the inflammatory status of degenerating IVD fragments obtained from patients undergoing discectomy; in addition we co-cultured in vitro Ad-MSCs and nucleus pulposus (NP) cells obtained from degenerated IVD tissue to understand whether Ad-MSCs are able to differentiate into an NP-like cell phenotype and/or to have a stimulatory effect on native NP cells.

Conclusions: Our results demonstrate that Ad-MSCs elicit immunomodulation on IVD fragments, and that Ad-MSCs co-cultured with IVD fragments show a commitment towards a NP-like phenotype. These data suggest a potential role of human Ad-MSC in regenerative therapy of IVD.