Intervertebral Discs

Photograph of a tissue-engineered intervertebral disc (right) and the native disc it is meant to replace (left). These implants have been successfully used to replace discs in the spine of rats. Unlike conventional medical implants, these engineered tissues integrate biologically with the surrounding vertebrae and their mechanical performance improves with time. For details see: Bowles et al, PNAS 108:13106, 2011.

Motivation
The primary cause of lower back pain is intervertebral disc (IVD) degeneration, with $90 billion spent annually on treatment. Current treatment options are limited and surgical intervention can cause further degradation of the adjacent discs and loss of range of motion. Because of these constraints, tissue engineered IVDs have become an increasing popular research target.

Current Research
1) develop a method to repair punctured discs and 2) develop a tissue engineered IVD as a possible biological replacement option.

Repair
High-density photocrosslinkable collagen gels have been developed in this lab as a means to “plug” a punctured disc and maintain disc height, a metric of disc health.

Replacement
Our lab has developed a composite tissue engineered IVD made from primary ovine nucleus pulposus (NP) and annulus fibrosis (AF) cells suspended in alginate and collagen respectively. These TE-IVDs have been shown to be effective in an in vivo model, when implanted in the caudal spines of rats. We are now focusing on improving the properties of our discs in vitro using mechanical loading and mesenchymal stem cells.