Notochordal Cells Promote Disk Matrix Formation by Mesenchymal Stem Cells and Nucleus Pulposus Cells

Abstract

IntroductionDisk degeneration is characterized by the inability of the resident cells to maintain disk tissue healthy due to a change of their phenotype and their decreasing number.1 Cell therapies have mainly focused on delivering adult mesenchymal stem cells (MSCs) to counteract this process. Though able to inhibit it, these cells could not restore the disk to a healthy state2,3 and complementary methods should be explored. The disk originally contains two cell populations: the nucleus pulposus cells (NPCs) and the notochordal cells (NCs). As NCs are not present in adult humans, their potential for disk regeneration has been poorly explored. We hypothesized that recreating the original cell combination of a developing disk (when the largest amount of matrix is produced) should induce discogenic cell phenotype and promote disk matrix formation. In the present study, NCs were combined with MSCs (used to complement the decreasing disk cell population) and to NPCs (representative of the native cell populati...