Autologous Stem Cell Therapy Maintains Vertebral Blood Flow and Contrast Diffusion Through the Endplate in Experimental Intervertebral Disc Degeneration

Study Design. Experimental, controlled, randomized, and paired study. Objective. To evaluate regenerative effect of stem cell therapy on the vertebral endplate and introduce dynamic contrast-enhanced magnetic resonance imaging (MRI) as a tool in the investigation of endplate function. Summary of Background Data. The vertebral endplate plays a crucial role in nutritional supply to the intervertebral disc. Estimation of endplate function is an important parameter in future biologic therapy of intervertebral disc degeneration (IDD). Methods. Four-level IDD was induced in each of 15 Gottingen minipigs. Percutaneous intradiscal injection of two hydrogels (Zimmer Biologics Inc, Austin, TX) and one loaded with stem cells was used as single interventions after 12 weeks. Total observation time was 24 weeks. MRI was performed before the initiation of treatment and killing of animals. Results. Three animals were excluded because of spondylodiscitis. Stem cell and hydrogel treatment had significantly higher T2 values, relative vertebral blood flow and volume, as well as lower Pfirrmann scores when compared with degenerative controls. No statistical differences were found compared to normal controls. Conclusion. Stem cell and hydrogel therapy is able to partly regenerate IDD and maintain perfusion and permeability of the vertebral endplate and subchondral bone. Dynamic contrast-enhanced MRI may become an important tool in future investigation of the vertebral endplate.