Abstract
Stem cell therapy for the intervertebral disc (IVD) is highly debated but holds great promises. From previous studies, it is known that notochordal cells are highly regenerative and may stimulate other differentiated cells to produce more matrix. Lately, a particular tissue-specific progenitor cell population has been identified in the centre of the intervertebral disc (IVD. The current hope is that these nucleus pulposus progenitor cells (NPPC) could play a particular role in IVD regeneration.
Current evidence confirms the presence of these cells in murine, canine, bovine and in the human fetal/surgical samples. Noteworthy, one of the main markers to identify these cells, i.e., Tie2, is a typical marker for endothelial cells. Thus, it is not very clear what their origin and their role might be in the context of developmental biology. In human surgical specimens, their presence is, even more, obscured depending on the donor's age and the condition of the IVD and other yet unknown factors.
Here, I revisit the recent literature on regenerative cells identified for the IVD in the past decades. Current evidence how these NPPC can be isolated and detected in various species and tissues will be recapitulated. Future directions will be provided on how these progenitor cells could be used for regenerative medicine and tissue engineering.
