The Role of the Endplate in Intervertebral Disc Degeneration and Regeneration

Philadelphia Va Medical Center, Philadelphia PA

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Abstract

Intervertebral disc degeneration and back pain place a significant burden on veteran health. Pathology of the cartilage and bony endplate adjacent to the disc is observed concomitant with disc degeneration, and is strongly associated with the occurrence of back pain. Despite this, there has been little research effort placed on regeneration of the vertebral endplate in conjunction with the treatment of disc degeneration. The objective of this proposal is to develop and evaluate a composite engineered biologic intervertebral disc and vertebral endplate construct as a strategy for spinal regeneration. This will be accomplished via two specific aims: Aim 1: Engineer biologic disc constructs with endplates (eDAPS) at multiple size scales (small animal to human) and evaluate the functional maturation and integration of these constructs with in vitro culture. In this aim, engineered discs will be fabricated at multiple size scales either with (eDAPS) or without (DAPS) the addition of porous polymer foam endplates. Constructs will be seeded with disc cells, and cultured in chemically defined media supplemented with TGF-?3 for up to 15 weeks. At each time point, the functional and compositional maturation of the constructs will be evaluated by MRI T2 mapping, histology, biochemical assays and mechanical testing. Aim 2: Determine whether vertebral endplate replacement enhances maintenance of engineered disc (DAPS) structure, composition and nutrition using a pre-clinical rabbit model. For this aim, pre- cultured DAPS alone (no endplate region), or eDAPS with or without hydroxyapaptite incorporated in the endplate region will be implanted in the rabbit lumbar spine for 12 weeks. Construct nutrition, vascularity, composition and mechanical function will be evaluated via in vivo post-contrast enhanced MRI, µCT, biochemical assays, histology and mechanical testing. It is anticipated that the results from this research will advance the clinical treatment of pain related to intervertebral disc and vertebral endplate degeneration. The proposed research will be combined with additional training and career development activities, including formal coursework, grant writing workshops, conference presentations, teaching and student mentoring throughout the duration of the career development award period. The research and training activities will be supported by Dr. Gullbrand's dedicated team of mentors, and will position her for success as a future independent faculty member and VA investigator.