Refine
Year of publication
- 2018 (2) (remove)
Language
- English (2)
Is part of the Bibliography
- yes (2) (remove)
Keywords
- Intervertebral disc (2) (remove)
Institute
Purpose Prolonged bed rest and microgravity in space cause intervertebral disc (IVD) degeneration. However, the underlying molecular mechanisms are not completely understood. Transient receptor potential canonical (TRPC) channels are implicated in mechanosensing of several tissues, but are poorly explored in IVDs. Methods Primary human IVD cells from surgical biopsies composed of both annulus fibrosus and nucleus pulposus (passage 1-2) were exposed to simulated microgravity and to the TRPC channel inhibitor SKF-96365 (SKF) for up to 5days. Proliferative capacity, cell cycle distribution, senescence and TRPC channel expression were analyzed. Results Both simulated microgravity and TRPC channel antagonism reduced the proliferative capacity of IVD cells and induced senescence. While significant changes in cell cycle distributions (reduction in G1 and accumulation in G2/M) were observed upon SKF treatment, the effect was small upon 3days of simulated microgravity. Finally, downregulation of TRPC6 was shown under simulated microgravity. Conclusions Simulated microgravity and TRPC channel inhibition both led to reduced proliferation and increased senescence. Furthermore, simulated microgravity reduced TRPC6 expression. IVD cell senescence and mechanotransduction may hence potentially be regulated by TRPC6 expression. This study thus reveals promising targets for future studies.
Degeneration of the intervertebral disc – triggered by ageing, mechanical stress, traumatic injury, infection, inflammation and other factors – has a significant role in the development of low back pain. Back pain not only has a high prevalence, but also a major socio-economic impact. With the ageing population, its occurrence and costs are expected to grow even more in the future. Disc degeneration is characterized by matrix breakdown, loss in proteoglycans and thus water content, disc height loss and an increase in inflammatory molecules. The accumulation of cytokines, such as interleukin (IL)-1 , IL-8 or tumor necrosis factor (TNF)-, together with age-related immune deficiency, leads to the so-called inflammaging – low-grade, chronic inflammation with a crucial role in pain development. Despite the relevance of these molecular processes, current therapies target symptoms, but not underlying causes. This review describes the biological and biomechanical changes that occur in a degenerated disc, discusses the connection between disc degeneration and inflammaging, highlights factors that enhance the inflammatory processes in disc pathologies and suggests future research avenues.