Introduction: Human Umbilical Cord Blood (HCB) Stem cell mediated therapy has the potential to restore the biological integrity of degenerated intervertebral disc. The effectiveness of HCB mesenchymal stem cells or chondroprogenitors for disc regeneration has not been tested.
Methods: An in-vivo rabbit model (n=20) of disc degeneration in the lumbar spine was created by flouroscopic guided needle puncture of the annulus fibrosis at the L2-3 and L4-5 level. The intervening L3-4 level acted as a control. At two weeks post puncture either the L2-3 or L4-5 laboratory created degenerated disc was subject to implantation of 1 million in 20ul i) undifferentiated human cord blood (HCB) mesenchymal stem cells (MSCs) or ii) differentiated HCB chondroprogenitor cells. Magnetic resonance imaging (MRI) was performed pre-operative, after inducing disc degeneration and 6 weeks post-implantation of stem cells. At 8 weeks rabbits were euthanized and control and experimental discs analyzed with H & E staining and immunohistochemical analysis. Biochemical analysis determined proteoglycan and glycosaminoglycan (GAG) content, and expression of specific markers to identify implanted cell viability.
Results: Successful extraction and culture mesenchymal stem cells from the umbilical cord was confirmed by specific surface antigen markers (CD90, 73, 29, 105, and 44). These cells were successfully differentiated into chondroprenitor cell found capable of producing GAG by alcian blue staining. MRI imaging indicated improved water content in disc injected with MSCs or chondroprogenitor cells compared to experimental degenerated disc which was not implanted with cells. H & E staining showed significantly more viable cell and extracellular matrix density in chondroprogenitor cell implanted degenerated disc. This was further confirmed with immuno-histochemical analysis of collagen type two content, implanted cell viability and disc rehydration.
Conclusions: HCB derived mesenchymal stem cells and chondroprogenitor cells appear to be effective in disc regeneration. However, differentiated chondroprogenitor cells appear better suited for restoration of cellular and extracellular matrix within the nucleus pulposis.
Patient Care: The potential to provide a biological disc restorative treatment for patients suffering from debilitating degenerative disc disease
Learning Objectives: To learn the use of umbilical cord blood derived stem cell use for intervertebral disc regeneration in an in-vivo animal model of disc degeneration.
References: In vivo intervertebral disc regeneration using stem cell-derived chondroprogenitors: laboratory investigation J. of Neurosurgery: Spine 10:3 pp 265-272, 2009.