Cell sources proposed for nucleus pulposus regeneration

Lower back pain (LBP) occurs in 80% of adults in their lifetime; resulting in LBP beingone of the biggest causes of disability worldwide. Chronic LBP has been linked to thedegeneration of the intervertebral disc (IVD). The current treatments for chronic backpain only provide alleviation of symptoms through pain relief, tissue removal, or spi-nal fusion; none of which target regenerating the degenerate IVD. As nucleuspulposus (NP) degeneration is thought to represent a key initiation site of IVD degen-eration, cell therapy that specifically targets the restoration of the NP has beenreviewed here. A literature search to quantitatively assess all cell types used in NPregeneration was undertaken. With key cell sources: NP cells; annulus fibrosus cells;notochordal cells; chondrocytes; bone marrow mesenchymal stromal cells; adipose-derived stromal cells; and induced pluripotent stem cells extensively analyzed fortheir regenerative potential of the NP. This review highlights: accessibility; expansioncapability in vitro; cell survival in an IVD environment; regenerative potential; andsafety for these key potential cell sources. In conclusion, while several potential cellsources have been proposed, iPSC may provide the most promising regenerativepotential.