Papers of the Week

The intervertebral disc (IVD) is an integral load-bearing tissue that derives its function from its composite structure and extracellular matrix composition. IVD herniations involve the failure of the annulus fibrosus (AF) and the extrusion of the nucleus pulposus beyond the disc boundary. Disc herniations can impinge the neural elements and cause debilitating pain and loss of function, posing a significant burden on individual patients and society as a whole. Patients with persistent symptoms may require surgery; however, surgical intervention fails to repair the ruptured AF and is associated with the risk for re-herniation and further disc degeneration. Given the limitations of AF endogenous repair, many attempts have been made towards the development of effective repair approaches that re-establish IVD function. These methods, however, fail to recapitulate the composition and organization of the native AF, ultimately resulting in inferior tissue mechanics and function over time and high rates of re-herniation. Harnessing the cellular function of cells (endogenous or exogenous) at the repair site through the provision of cell-instructive cues could enhance AF tissue regeneration and, ultimately, improve healing outcomes. Here, we review the diverse approaches that have been developed for AF repair and emphasize the potential for mobilizing the appropriate cellular players at the site of injury to improve AF healing.