Intervertebral disc (IVD) degeneration is a prominent cause of low back pain. IVD cells expressing angiopoietin-1 receptor Tie2 represent a progenitor cell population which decreases with progression of IVD degeneration. Homing of mesenchymal stem cells (MSCs) is a physiological mechanism aiming to enhance the regenerative capacity of the IVD. The purpose of this study was to assess the effect of MSC homing on the Tie2 positive IVD progenitor cell population, the IVD cell viability, and the proliferative phenotype of the IVD cells. Human MSCs were isolated from bone marrow aspirates and labelled with fluorescent dye. Whole IVDs with endplates were harvested from bovine tails; MSCs were placed on the endplates. Human traumatic, degenerative and healthy IVD tissues were obtained from patients and organ donors. MSCs were added onto tissue samples. After 5 days, IVD cells were isolated. Percentages of Tie2 positive, DAPI positive (dead) and Ki-67 positive (proliferative) IVD cells were determined. MSC homing or co-culture significantly increased the proportion of Tie2 positive progenitor IVD cells in bovine and 7/10 human IVDs, decreased the fraction of dead IVD cells in bovine and 7/10 human IVDs, and induced a proliferative phenotype in bovine and 5/6 human IVDs.Background and Purpose
Methods and Results
