Development of inervertebral disc with functional nucleus pulposus for clinical application

Abstract

Lower back pain caused by degenerative disc disease are getting more common in the society. Current treatments available such as spinal fusion and artificial disc displacement are able to relieve pain but fail to restore the function of intervertebral disc (IVD) and associated with side effect. This has led to increase interest in tissue engineering of IVD which aim to regenerate tissue’s native function through scaffold, cell and/or bioactive agent. In this project, the role of nucleus pulposus chondrocyte (NPC), human mesenchymal stem cell (hMSC) and growth factors in tissue engineering of nucleus pulposus (NP) was investigated. NPC was sorted base on its physical size into smaller and bigger size population. Through gene expression analysis and F-actin staining, smaller size population was found to be able to form NP tissue construct that synthesis higher level of major NP matrix component such as aggrecan and Type II Collagen. Expansion of isolated patient’s cell has been the prerequisite for tissue engineering but it is associated with de-differentiation. Therefore, the role of hMSC and effect of encapsulated growth factors in forming NP tissue construct was studied. It was found that hMSC was able to express more NP matrix when encapsulated with both transforming growth factor beta 3 (TGF-β3) and platelet-derived growth factor-BB (PDGF-BB) than each growth factor alone. The result of this project showed that cell encapsulating hydrogel has the potential to be applied clinically with the injectable property of hydrogel that allowed surgery to be carried out in minimal invasive way.