A decrease in the population of a specific subset of progenitor cells in the jelly-like substance in the middle of intervertebral discs, known as the nucleus pulposus, is linked to aging and degeneration of the discs, reports a study in Nature Communications this week. These findings reveal new insights into the mechanisms that maintain the integrity of the nucleus pulposus and intervertebral discs.
During the process of aging, the functional ability of intervertebral discs changes and the cells enter a state of cellular senescence, a growth-arrest program that limits the lifespan of mammalian cells and prevents cell proliferation. Daisuke Sakai and colleagues hypothesised that this might be due to a dysfunction of progenitor cells. They studied mouse and human nucleus pulposus samples to determine if this was true and identified a subset of progenitor cells that decreased with age and degeneration. When they transplanted human progenitor cells into immune-deficient mice, they observed self-renewal activity of the cells in various tissues of the mice.
The authors suggest that identifying the profile of these special cells will aid in the development of therapeutic strategies against intervertebral disc degeneration, which is implicated in many debilitating and painful disorders.